- Responses of Seed Germination, Seedling Growth, and Seed Yield Traits to Seed Pretreatment in Maize (Zea mays L.)
- 1. Introduction
- 2. Materials and Methods
- 3. Results
- 4. Discussion
- 5. Conclusions
- Conflict of Interests
- Authors’ Contribution
- Cheap Seed Starting – How To Germinate Seeds At Home
- How to Germinate Seeds
- Factors That Affect Seed Germination
- Seeds 101: Where To Acquire And How To Germinate Seeds
- Picking And Acquiring Seeds
- What Is Seed Germination?
- Requirements For Germination
- How To Germinate Seeds
- What’s The Best Way To Germinate Seeds?
- Using The Right Nutrients And Water Supply
- Subscribe For More Resources Or Contact Us For Help
- How to Germinate Your Own Pot Seeds
- Germination Methods
- Paper Towel Method
- Submersion Method
- Rockwool Method
Responses of Seed Germination, Seedling Growth, and Seed Yield Traits to Seed Pretreatment in Maize (Zea mays L.)
A series of seed priming experiments were conducted to test the effects of different pretreatment methods to seed germination, seedling growth, and seed yield traits in maize (Zea mays L.). Results indicated that the seeds primed by gibberellins (GA), NaCl, and polyethylene glycol (PEG) reagents showed a higher imbibitions rate compared to those primed with water. The final germination percentage and germination rate varied with different reagents significantly (). The recommended prime reagents were GA at 10 mg/L, NaCl at 50 mM, and PEG at 15% on account of germination experiment. 15% PEG priming reagent increased shoot and root biomass of maize seedling. The shoot biomass of seedlings after presoaking the seeds with NaCl reagent was significantly higher than the seedlings without priming treatment. No significant differences of plant height, leaf number, and hundred-grain weight were observed between control group and priming treatments. Presoaking with water, NaCl (50 mM), or PEG (15%) significantly increased the hundred-grain weight of maize. Therefore, seed pretreatment is proved to be an effective technique to improve the germination performance, seedling growth, and seed yield of maize. However, when compared with the two methods, if immediate sowing is possible, presoaking is recommended to harvest better benefits compared to priming method.
In semiarid area, seasonal drought is often frequent in spring and autumn, especially in the sowing season. Soil evaporation will lead to a large amount of moisture loss, of which 90%–95% occurred in 5–10 cm soil layer , that is, the optimum depth for crop sowing. Under this condition, it is important to improve the water use efficiency of crop seedlings or find some ways to increase crop yield under drought conditions .
Maize (Zea mays L.) is an important crop in the world; it is widely used for feed and industrial raw material. Maize ranks the third in world production following wheat and rice for the area and production. It is also the main crop in northern China, where the climate is a combination of temperate and semiarid monsoon. Rapid and uniform field emergence is an important factor to achieve high yield to meet the growing demand for food .
Seed priming is a presowing treatment that exposes seeds to a certain solution that allows partial hydration but not germination , and redried to original moisture content. Although the germination is not completed, metabolic activities that prepare seeds for radicle protrusion may be initiated during priming . Many evidences have shown seed priming could improve germination and early seedling growth under stress conditions compared to plants grown from untreated seed .
Various priming treatments have been developed to increase the speed and synchrony of seed germination . Common priming techniques include hydropriming (soaking seed in water), osmopriming (soaking seed in osmotic solutions such as PEG), halopriming (soaking seed in salt solutions), and priming with plant growth hormones. However, different priming effects were reported with different priming reagents and species. For instance, when Lolium perenne seeds were primed with PEG solution, the germination was significantly improved, but no obvious effects were observed with Festuca rubra, Festuca ovina, and Poa trivialis . Seed priming with optimal concentrations of plant growth hormones, such as auxin (IAA), gibberellins (GA), abscisic acid, and ethylene, has proven that germination performance as well as growth and yield of many crop species under both normal and stress conditions could be improved effectively . By soaking seeds (sorghum, rice, or wheat) in water and planting the same day (so-called presoaking treatment), the germination rate could also be increased and seedling emergence improved .
In recent years, numerous studies were devoted to the physiological responses of seed germination and seedlings stages to chilling or osmotic stress ; the ecological responses of the whole growing season remain largely unknown. To elucidate the ecological responses of different pretreatment to maize species, it may be useful to investigate the changes in not only germination stage, but also seedling growth and yield responses. Few studies to date have attempted to test the whole growing season response to different pretreatments. In this study, we choose water, PEG, NaCl, and GA as different priming reagents, to investigate the dynamics of seed water uptake during seed priming, germination and seedling growth responses after seed priming and presoaking, and yield response to different pretreatment.
2. Materials and Methods
Four experiments were conducted at Jilin Agricultural University. Seeds of maize (Zea mays L.) cv. Jinong 610 were used as test materials. All seeds were pretreated with 0.1% H2O2 solution for 5 min and then thoroughly washed for 5 min prior to seed treatments.
2.1. Experiment 1: Seed Priming Experiment
Thirty seeds were placed in two layers of filter paper in a 12 cm Petri dish. The filter paper was moistened with about 30 mL of different priming reagents, ensuring that the seeds were immerged with solutions. Seeds were primed in different priming reagent solution in the lab with room temperature 14°C to 21°C and relative humidity 48% to 64% at night and during day, respectively.
At the hydration stage, the seeds were weighted every 4 h after the surface solutions were dried with filter paper until the weight of seeds was not changed (seeds were saturated). On the dehydration stage, seeds were placed in dry Petri dishes and weighted every 4 h to original weight .
The water content of seeds and rate of hydration was calculated with the following formula: where is the weight when the seed was saturated with different solutions and is the original weight.
2.2. Experiment 2: Germination Experiment
The germination experiment was conducted at growth chambers (HPG-400, Haerbin, China) at relative humidity of 60% with 12 h photoperiod (Sylvania cool white fluorescent lamps, 200 mmol m−2 s−1, 400–700 nm, 25/15°C).
The primed seeds under different priming reagents from Experiment 1 were germinated in Petri dishes (12 cm diameter) containing two layers of filter paper with 15 mL of distilled water. Each Petri dish contained 30 seeds representing an experimental unit. The seeds were considered to have germinated after radicle emergence. Germination test was ended when no seeds have germinated for 3 days. The germination period was 12 days.
The rate of germination was estimated using a modified Timson’s index of germination velocity , where is the percentage of seed germination at one-day intervals and is the total germination period . The maximum value possible for our data using this index was 100 (i.e., 1000/10). The greater the value, the more rapid the rate of germination.
2.3. Experiment 3: Seedling Response to Seed Treatments
There were two seed treatment methods (priming and presoaking) and 4 seed treatment regents (water, 50 mM NaCl, 15% PEG, or 10 mg/L GA) with untreated seeds as control. The experiment was a 2 × 4 factorial design, replicated 5 times.
Seeds were either primed as described in Experiment 1 or presoaked using regents mentioned above. Those solutions were selected based on the results from Experiments 1 and 2, which were the best expressive concentrations of each reagent to prime the seeds.
The experiment was conducted in a glasshouse but partially shaded under maximum photosynthetically active radiation of 1000 μmol m−2 s−1, day/night temperature of 30/24 ± 3°C. Seeds were sown in 25 cm diameter plastic pots that contained 4 kg of native loamy soils. Ten seeds were sown with 3 cm depth in each pot and then thin to 5 seedlings after geminating. Pots were destructively harvested 40 days after seed germinated.
Seedling height, root length, and the biomass of different organ parts were measured at harvest.
2.4. Experiment 4: Yield Response to Seed Treatments
The experiment was conducted in the field. Seeds were pretreated as mentioned in Experiment 3. The experimental design was identical to Experiment 3, but replicated 3 times.
Two or three seeds were sown every 40 cm at the bottom of the ridge and then covered with about 5 cm of soil in a 50 m long row as one plot. At the three-leaf stage plants were thinned to one per hole. Each plant received 5.3 g urea/per plant (200 kg urea/ha) on the surface of the soil 10 cm from the plant when it reached the eighth leaf stage. Weeds, insects, and diseases were controlled adequately when necessary.
Ten successive plants per plot were randomly selected at physiological maturity stage. The leaf number and shoot height were measured before harvest. Grain yield and 100-grain weight were determined by oven drying samples at 65°C. Yield was expressed as t/ha.
2.5. Data Analysis
Analysis of variance (ANOVA) was conducted using Statistics SPSS 19.0. Water intake and imbibition rate in Experiment 1 were analyzed using repeated measures. One-way ANOVA was performed for data from Experiment 2 and two-way ANOVA was employed for data from Experiments 3 and 4. The treatment mean values were compared with the least significant difference (LSD) at the 5% level.
3.1. Experiment 1: Seed Water Intake under Priming Cycle
The water intake of maize seed showed similar trends in different priming reagents. The percentage of water intake was greater at the first 12 hours then slowed down. It took about 44 h for the seeds to be saturated (Figure 1). When comparing different concentrations of different solutions with water (control), the water intake with 250 mM NaCl was significantly lower than control, and all the three concentrations of PEG showed slower water intake than control. No significant differences were observed between GA and control. One hydration-dehydration cycle lasted about 84 h.
(c) Figure 1
Effects of pretreatment reagents on water intake under priming cycle ( ).
The imbibitions rate of seeds was increased after one hydration-dehydration cycle (Figure 2). Compared with water priming, the seeds showed a higher imbibitions rate when primed by GA, NaCl, and PEG reagents. The imbibitions rates were significantly higher when primed with NaCl (150 and 250 mM), GA (15 mM), and all the three concentrations of PEG compared with those primed in water (Figure 2).
(c) Figure 2
Effects of pretreatment reagents on imbibition rate after seed priming ( ).
3.2. Experiment 2: Germination Responses after Seed Pretreatment
The seed pretreatment of different reagents had significant () effects on the final germination percentage and germination rate (Figures 3(a) and 3(b)). Primed seeds had significantly higher germination percentage than those in control, but no significant differences were observed among priming reagents. The germination rate was also significantly increased by seed priming except 20% PEG. GA showed greater effect on germination rate, and PEG had slightly increased germination rate when compared with other reagents. No statistical differences were observed between water and NaCl priming methods ().
(b) Figure 3
Effects of pretreatment reagents on final germination percentage and germination rate of maize ( ).
Within each reagent, the concentration of different priming reagents also showed different effects to germination percentage and germination rate. The optimum germination performance was observed after priming with 10 mg/L GA, 50 mM NaCl, and 15% PEG, which were used for Experiments 3 and 4.
3.3. Experiment 3: Seedling Response to Seed Pretreatments
No significant differences were observed in plant height and root length after priming by different reagents (Figure 4). The shoot and root biomass of maize seedlings were significantly affected by priming reagents (Figure 5 and Table 1). Pretreatment methods (priming and presoaking) also significantly affected the root biomass (). The shoot and root length showed no remarkable differences by the interaction of priming reagents and pretreatment methods in this pot experiment. Priming treatment with PEG reagent significantly increased shoot biomass compared to the control group. The shoot biomass was also significantly higher when presoaking with NaCl reagent compared to control. However, no significant differences were observed in root biomass between treatments.
Table 1 Analysis of variance for seed priming effects on maize for seedling growth and yield composition ( , ).
Effects of pretreatment reagents and priming methods on seedling shoot height and root length of maize ( ; ns: not significant).
Effects of pretreatment reagents and priming methods on seedling shoot and root biomass of maize ( ).
3.4. Yield Response to Seed Pretreatment
There was no significant difference in plant height between seed pretreatments. Presoaking with PEG and GA significantly increased the leaf number when compared with control. No significant differences were observed to the seed yield and hundred grain weight between different priming reagents (Table 1). But compared with priming methods, presoaking with water, NaCl, or PEG significantly increased the hundred-grain weight of maize (Table 2).
Table 2 Effects of pretreatment reagents and priming methods on yield composition of maize ( ).
The study revealed that seed priming and presoaking techniques using different solutions can significantly improve maize plant performance by increasing seed germination rate, seedling biomass, and seed yield, although response varied with different solutions and concentrations. Seed priming with different concentrations of solutions significantly improved germination performance, but no remarkable differences were observed for seedling growth and seed yield, while seed presoaking with some solution dramatically improved seedling growth and seed yield of maize.
Germination and seedling establishment are critical stages which affected both quality and quantity of crop yields . Soil water content is the key factor affecting seed germination and plant establishment in the semiarid area. The present study showed that, compared with the control group, the rate of hydration increased dramatically after seed primed by reagents. This implies that seed priming may improve seed germination of maize seeds by speeding up imbibition, which could contribute to facilitate emergence phage of maize after raining in the semiarid area. Similar results were also reported that priming improved germination of sunflower cultivars by accelerating imbibitions .
Generally, seed germination entails three distinct phases: (i) imbibition, (ii) lag phase, and (iii) radicle growth and emergence . The purpose of priming is to prolong the lag phase, which allows some pregerminative physiological and biochemical processes to take place but prevents germination . The results of our germination tests indicated that seed priming significantly increased the final germination percentage and germination rate of maize. The increment in seed germination due to seed priming treatment is in conformity with other researchers . When compared with different priming reagents, GA of all concentrations showed greater influence on germination rate. It was reported earlier that GA participated in regulation of many growth and developmental processes in plants and was particularly important in regulating stem elongation . GA treated seed was closely associated with their rapid utilization in the synthesis of various amino acids and amides , which could be the reason for the increased germination rate.
Priming reagents (especially for PEG priming) had the beneficial effects on shoot and root biomass. This was mainly due to the accelerated metabolism occurring in primed seeds, which increases the imbibition speed as compared to unprimed seeds. Similar results were also reported by Guan et al. on sorghum seeds. Farooq et al. reported that presoaking with inorganic salts improved seedling emergence, shoot and root length, and biomass. In contrast, no significant differences were observed for plant height, root length, and biomass in the present study. Only presoaking with NaCl solution increased shoot biomass, which had a similar trend with the study by Farooq et al. .
Increasing evidence suggests that seed priming could change the crop performance from physiological, biochemical, and molecular aspects . There are several studies arguing that the priming itself could be a stress, for the water uptake activates previously quiescent cellular events in primed seeds while compromising the desiccation tolerance . Chen and Arora also concluded that primed seeds, no matter what the priming scheme that was chosen, would inevitably endure some injury by the dehydration treatment. Only few studies reported that seed priming could increase the grain yield as shown by Sharifi and Khavazi with plant growth promoting Rhizobacteria (PGPR). However, in the current study, no significant difference in grain yield was observed in priming treatments while presoaking with water, NaCl, and PEG solutions did significantly increase the grain yield. Harris et al. also reported that presoaking followed by surface drying has more advantages to yield in many field crops.
The results indicated that the final germination percentage and germination rate varied with different reagents significantly (). The GA at 10 mg/L, NaCl at 50 mM, and PEG at 15% were recommended on account of germination experiment. 15% PEG priming reagent increased shoot and root biomass of maize seedling. The shoot biomass of seedlings after presoaking the seeds with NaCl reagent was significantly higher than the seedlings without priming treatment. No significant differences of plant height, leaf number, and hundred-grain weight were observed between control group and priming treatments, while presoaking with water, NaCl, and PEG solutions did significantly increase the hundred-grain weight of maize. Our results confirmed that seed pretreatment is an effective technique to improve the germination percentage, germination rate, seedling growth, and seed yield. However, if immediate sowing is possible, presoaking is recommended to harvest better benefits compared to hydration–dehydration method.
Conflict of Interests
The authors declare that there is no conflict of interests regarding the publication of this paper.
Yu Tian, Daowei Zhou, and Bo Guan contributed equally to this work.
The authors were grateful to all the laboratory members for continuous technical advice and helpful discussion. This project was financially supported by Shandong Province Natural Science Fund (no. ZR2012CQ017) and National Natural Science Foundation for Distinguished Young Scholar of Shandong Province(no. JQ201114). The authors would like to thank the editor and the anonymous reviewers for their helpful comments.
Seeds have everything they need to continue their species built right into them. All of the accumulated adaptations, the wide range of environmental and seasonal conditions that they have encountered and grown through are encoded into their genetic material, their DNA. Everything they need to remain dormant, and then sprout when the time is right is built right inside their shells. Within that hard seed coat is enough food energy to help them break dormancy and carry them into their first several days as seedlings. All the enzymes they need to convert the stored energy into food is there as well; they have all of the fats, carbohydrates, protein, enzymes and hormones needed to get the seed off to a great start. As home gardeners and small scale growers, it is our job to provide those proper conditions to ensure maximum germination into strong and healthy seedlings that are ready to transplant into the garden when the conditions are right.
In natural systems, the top of the soil network where the loose leaf matter or detritus of last season begins to decay is loose and allows light to penetrate the topmost layer. It is usually not compacted or dense at all. Water vapor is present in this layer of natural mulch, along with some inherent decomposition helping to boost the temperature slightly. The seed sprouts, receives the diffuse light and builds strength as it works to push through the network of organic matter. When it has enough strength, it breaks through that layer which then becomes a protective mulch slowly breaking down and feeding the plant. To help germinate the strongest and healthiest seedlings possible, we need to follow this pattern as closely as we can.
In most parts of North America, some seeds will need to be started indoors as they need a consistent temperature and the colder nights will slow the process down greatly. Heat mats or heating pads will speed the germination process up, sometimes sprouting seeds in just a few days. Even with a greenhouse, unless it is a heated greenhouse, starting seeds indoors and then moving them into the greenhouse when they are up and have their first set of true leaves is a much better way with less loss of seedlings. We have had great success with starting seeds on heat mats inside, then transferring them to a cooler greenhouse with heat mats set at a lower temperature to keep the roots warm overnight. This gives the seedlings the cooler environment that they need for strong, healthy growth but keeps the roots warm during the nightly temperature drops. Heirloom Seed Starting Made Easy shows a short video of exactly how we do it!
Varieties most frequently started inside are tomatoes, peppers and eggplant. Many other crops such as radish, cabbage, lettuce, pumpkin and squash can be started inside and transplanted into warm soil for intensive gardening. Some herbs and flowers need to be started inside. Remember to refer to the growing instructions for each variety on the back of the seed packet for recommended sowing methods.
Cold frames can act as miniature greenhouses and are easy to build from 1 x 2″ wood and heavy poly sheeting from home improvement stores. Build it 2 – 3 feet tall so that the plants have room to grow, but you can still reach into it easily enough. A hinged roof allows for venting on warmer days. A 3 x 5 foot size is ideal for the home gardener as it is large enough to hold a good number of plants yet small enough to cover with a moving blanket or something similar on nights that will be cold and keep the plants healthy without moving all of them inside each night. A gallon milk jug or two of hot water in the cold frame before covering will get you through a fairly cold night with no problems to your tender seedlings. If needed, it is easy enough to build one or two more cold frames to accommodate the plants as they get larger without crowding them together. Successful Heirloom Seed Starting for the Home Gardener shows the advantages of starting your own seeds, along with planning and arranging what simple equipment is needed.
What does a seed need?
Moisture and temperature are the two most important aspects for vigorous seed germination, followed by a few other factors. Let’s take a closer look!
Moisture must be at a constant level for the seed and young seedling as they have no moisture reserves in themselves like a mature plant does. A mature plant can go without moisture for a short period of time, sometimes up to several hours, but a seedling will die if it loses its critical moisture level even for a few minutes. The seed needs enough moisture to start the process of germination; but not too much as to prevent oxygen from reaching the seed, as respiration increases dramatically. Water initially starts the process by softening and splitting the seed coat, then activates nutrients, enzymes and hormones to convert stored foods into energy. Finally it serves as a means of transporting nutrients to all parts of the newly emerging plant. Watering from the bottom is the best method of keeping the moisture levels more consistent. Misting can help correct smaller areas that aren’t quite moist enough. Many seedling trays will have a bottom tray to help water the soil.
Warm Soil Temperature
The soil temperature must be correct to initiate the germination process. The key is the temperature of the soil, not the surrounding air. A room that has an air temperature of 70F may have a soil temperature of 60F or less, as the moist soil acts as an evaporative cooling medium, reducing the soil temperature below what is needed. At too low a temperature the seed remains dormant, often for an extended amount of time. Not only the ideal temperature is needed, but for the correct amount of time. This prevents the seed in the wild from germinating too early and being killed by the next frost or cold front that moves in. If the temperature swings too much from the daytime high to the nighttime low, the seed will not germinate, or do so very slowly. A constant temperature for a week to 10 days will have almost all vegetable seeds up and going well.
The relationship between temperature and light changes as seeds germinate. Seeds need a high moisture and very warm environment to germinate. Both moisture and temperature levels need to be pretty constant to get good germination. If the temperature is high during the day and cooler at night, the germination will be really delayed. In the sprouting phase, the soil should be almost – but not quite – wet, with a shine or sheen to it when a light is above the soil. It should leave a fingertip moist after gently pushing on the soil surface. Ideally, tomatoes and peppers need 85F soil temperature to sprout. Most cool season vegetables we eat today need a soil temperature above 70F for best germination, with varieties like carrots and cauliflower needing 80F. Squash, radish, okra and pumpkin will germinate best at 95F!
The soil needs some type of fertility to feed the young seedlings, not a lot but some. The seed provides the energy and nutrition needed to get the sprout off to a good start, but after the initial few days everything is dependent on the seedling developing leaves to start the photosynthetic process to provide its energy and build its reserves. Some very important nutrients will come from the soil. Seed Starting Media for the Home Gardener shows what different types of media are used for, with a couple of good seed starting soil “recipes”!
What exactly is going on while the seed is germinating?
Many think of germinating as being the equivalent of sprouting, but that’s not exactly true. Germination is the entire process the seed undergoes resulting in a seedling. The sprouting processes are the final steps in germination, with the emergence of a root tip and leaf from the seed coat. There is much that goes on inside before we get to see any results.
Inside the Seed
The first thing that happens is the seed must absorb water to start the entire germination process. The water is taken in through close contact with the soil and depends on several factors of the seed itself. The hardness or permeability of the seed coat determines how much water can be taken up in a certain amount of time. Of course the amount of water available to the seed is highly important as well, showing that a constant supply of moisture is critical to starting the germination process off right.
This uptake of water softens the seed coat, which eventually splits open to allow the root tip to emerge. At the same time the seeds metabolism goes into high gear as the seeds internal tissues absorb moisture and food that was stored in an inactive state inside the seed is transformed into energy. Starches are converted to simple sugars and proteins into amino acids. Enzymes are activated, furthering the metabolic process of breaking dormancy and becoming a living plant. Hormones are also activated, controlling how much and where newly produced foods are transported to. Oxygen uptake increases greatly. New tissue starts to grow, first at the root tip, then the stem, the bud and cotyledons or embryonic leaves. Peas synthesize new compounds within the first 24 hours of starting germination. Lettuce seeds start producing new tissue about 12 hours after the onset of germination, concentrating in the root cells.
Outside the Seed
While all of this is going on inside the seed, not much will be noticed on the outside, at least not yet. The pots, cubes or flats that the seeds are planted in need to be checked at least once a day and the soil kept moist but not soggy. Steady heat needs to be maintained and air should reach the soil to allow the seeds to breathe and keep mold from forming on the soil surface. If you do find mold starting to grow, let more air in. If there is a lid on the seedling tray, remove it for a few hours or put a small fan where it can circulate a small, gentle amount of air and the mold will usually disappear.
Changes for the Seedling
Once the seedlings are up, temperature and moisture needs change. Once the seedlings start putting on their first set of true leaves, they need less moisture and slightly cooler temperatures for continued growth. This is where beginning gardeners usually make their first mistake, by keeping the moisture levels high once the seedlings have sprouted. This can create what is known as “damping off”, which is characterized by a loss of growth in the seedling. It will have a somewhat wilted appearance with a slightly constricted stem right at soil level. There may be almost invisible flying fungus gnats swarming around. If this condition is not corrected immediately, the seedlings will fall over and die due to a fungal attack at the base of the stem. It is easily avoided by reducing the amount of water by about 10% over a few days after the seedlings sprout and start growing their first true leaves.
Temperature should be reduced, as overly warm conditions create weak, spindly and sappy growth that becomes difficult to manage. Start seeds in a warm environment and grow seedlings in a slightly cooler one. A 10 – 15F reduction in temperature is all that is needed for strong and vigorous growth.
Steady and strong light is needed once the seeds have started to germinate and need to start photosynthesis to provide energy for themselves. Light from a window is sometimes not enough, and the seedlings will fail. Two of the biggest killers of seedlings are too much water and not enough light. Seedlings will get really “leggy” or tall, pale spindly with too little light, as they stretch to find more light. Once seedlings are up they need a lot of light, more than most people think. There is no harm in providing too much light, as the plant will use as much as it needs and then stop using the light energy. The danger to lots of light is in drying out the soil, especially when using high powered grow lights or a very warm south-facing sunny window with seedling trays in it. If the soil dries out, the seedlings will die very quickly. This is something that is easy to monitor and correct with close observation, and can be avoided with a bottom-watering setup.
With some diligent daily observation and a tiny bit of luck, within a couple of weeks the new seedlings will be ready for transplant into a larger pot or directly into the garden, depending on the weather and timing of your seed starting. This may all sound very complex and complicated, however, please realize that seeds have been germinating and producing new plants for untold millennium without our help. We as home gardeners are just trying to help the process along, allowing us to have much better production from our garden than we could ever get by sowing all of our seeds directly into the soil. A Garden Journal is a great tool to record the successes and challenges of your seed germination project, so that you can see ways to improve or experiment with your particular process next year. Most gardeners develop very effective methods for seed starting within just a couple of years and only fine tune the process from there.
Cheap Seed Starting – How To Germinate Seeds At Home
Many people will tell you that one of the most expensive parts of gardening is buying the plants. The best way to avoid this problem is to simply grow your own plants from seeds. Once you learn how to germinate seeds, you will always be able to have cheap plants.
It’s easy to get started with cheap seed starting. Let’s look at how to germinate seeds.
How to Germinate Seeds
Start with seeds that are less than two years old, a soilless seed starting medium of some kind and a container that can help hold moisture in.
Soilless seed starting medium – A soilless seed starting medium will insure that the seeds and seedlings are not killed by too much salt (or salinity) which is frequently found in soil or even regular soilless mixes. The soilless seed starting medium can be an actual soilless seed starting mix (bought at your local nursery) or a folded paper towel. If you choose to use a paper towel, you will need to move the germinated seeds to soil or another growing medium after they have sprouted.
Container – This container should hold in moisture. A plastic container is ideal for this. Some people may use a Tupperware container while others may use a zip lock bag.
Dampen (but do not soak) the soilless seed starting medium and place it in the container.
- Place the seeds in the soiless medium
- Close the container
- This will ensure that the seeds continuously receive the appropriate amount of moisture
Now, find a warm place to put your seeds (which is another one of the factors that affect seed germination). Keep your seed germination container out of direct sunlight, even if the packet specifies they need sun to germinate. If you need the sunlight, place in indirect light. Many people find that the top of their refrigerator is ideal, but you can use a heating pad set very low or even the top of your TV; anywhere that has a very low steady heat.
Check your seeds often to see if they have sprouted. Germination time for seeds varies and should be marked on the seed packet. Once they have sprouted, vent the container by opening it some. If using a paper towel, move the seedlings to proper soil, otherwise transplant seedlings when they have two true leaves.
Factors That Affect Seed Germination
Factors that affect seed germination vary from plant species to species. But there are a few that are standard. If the seeds that you are growing are not germinated in what is considered a standard way, the seed packet will state this in the directions. Factors that affect seed germination are:
Contrary to popular belief on how to germinate seeds, sunlight is not a standard factor that influences seed germination (unless otherwise stated on the seed packet). In fact, sunlight can do more harm than good, as it may overheat the seeds and seedlings, killing them.
Now you know how to germinate seeds with cheap seed starting mix, you can grow your own cheap plants.
Seeds 101: Where To Acquire And How To Germinate Seeds
When first starting out, many growers get hung up on whether they should grow from seeds or from clones. In some cases, the decision may be made for you — for instance, if you don’t have access to a mother plant, seeds will be your only choice.
Once you’ve decided that you’ll be growing from seed, you’ll need to answer a couple more questions:
- How will you pick your seeds and from where will you acquire them?
- How will you germinate those seeds?
In today’s article, we’ll look at how to pick and acquire seeds as well as how to germinate them.
Picking And Acquiring Seeds
If you’ve decided to start your garden from seeds, you’ll need to make a few more decisions before commencing your grow — namely, the specific type of plants you want to cultivate and how you’ll go about acquiring the right seeds.
The first and most obvious question to answer is: What kind of plants do you want to grow? If you already know the particular strain that you want to cultivate, it can make your search a little easier.
On the other hand, if you’re not quite sure exactly which plant to grow, you’ll need to do some preliminary research. What specific types of effects are you looking to achieve? Certain strains are associated with particular effects, so do your homework and narrow down your choices before you begin the search for seeds.
When you’re ready to acquire seeds, there are a couple of options available. One option involves ordering from an online seed bank. Another option is to obtain seeds from a local breeder, if there are any in your area.
This second method is advantageous for a couple of reasons. You’ll already know that the plant is well adapted to your local environment and can grow in the conditions you’ll provide, which can save you a lot of time and effort.
Once you’ve obtained your seeds, you’re ready to start growing. But before we dive into how to germinate seeds, let’s first talk about what germination is and what happens during germination.
What Is Seed Germination?
Put simply, germination is the first stage of plant growth when you’re starting from a seed — essentially, it’s seed starting. During germination, the seed absorbs water through its seed coat. Once it starts receiving moisture, growth begins to occur inside the seed.
As growth continues, the seed slowly opens as the embryonic root, also known as the radicle root, begins to emerge.
Once the radicle root has sprouted from the seed, it’s time to transplant it into your grow medium.
Requirements For Germination
In order to germinate, your seeds need the right conditions and proper temperature. But don’t be intimidated — germinating seeds is relatively easy, and you’ll get better with practice.
During germination, seeds need to be in a dark, warm, moist climate. Aim for a seed germination temperature between 74 and 78 degrees Fahrenheit.
It’s also a good idea to only germinate a few of your seeds at a time, especially if you’re a beginner. For instance, if you have 10 seeds total, try germinating and growing three of them to begin with. This way, you’ll gain some experience and be able to experiment with germinating and grow methods to find out what works and what doesn’t work.
Once the first three seeds have germinated and been transplanted to their grow media, move on to the next three seeds. From there, germinate the last four seeds once you’ve had a couple of chances at germinating and growing your plants.
Now, let’s look at how to germinate seeds.
How To Germinate Seeds
There are a few different methods for germinating seeds. Let’s take a look at the most popular ones.
1. Paper Towel Germination
One of the most popular ways to germinate seeds is the paper towel method. To do this, you’ll need paper towels as well as two plates.
The first step is to dampen one of the paper towels and set it on one of the plates. You want the paper towel to be completely wet, but not so much that it’s dripping water or pooling on the plate.
You’ll then place the seeds onto the damp paper towel. Don’t crowd the seeds together — spread them around the paper towel and leave plenty of room between them.
Then place another moist (not soaking or dripping wet) paper towel on top of the seeds. Gently press the paper towel down on top of the seeds to ensure they are completely enveloped between the paper towels.
Finally, place the second plate upside down over the seeds in a clamshell-like fashion. This will provide the dark environment your seeds need to germinate.
You’ll want to check on the seeds every day to monitor their progress and ensure they don’t run out of moisture. If the paper towels start to dry out, dampen them again with a spray bottle.
Germination time can vary, but generally the seeds should open up within a few days of starting the germination process. Once the radicle roots have emerged and grown to a few millimeters in length, you’ll be ready to transfer your seedlings into the grow medium.
2. Grow Medium Germination
Another common germinating method is to place the seeds directly into a grow medium. However, you must be careful with this method; seeds are very sensitive to nutrients, and germinating them in a nutrient-rich environment can actually cause them damage.
Common media for seed germination include rockwool cubes, coco coir pods, or a seedling starter fertilizer. The basic idea here is the same as the paper towel method: You’ll dampen the media, insert the seeds, then keep them in a warm, humid environment until the radicle root emerges.
Once the seedlings have sprouted, you can transfer them directly to your hydroponic system or soil.
What’s The Best Way To Germinate Seeds?
For beginners, the paper towel method is tried-and-true. We recommend using this method for growers who are just starting out.
If you’re a seasoned gardener with experience using different grow media, the second method may be more appropriate for you. It all comes down to your personal preference.
Using The Right Nutrients And Water Supply
It’s important to remember that seedlings are sensitive to nutrients, so you want to make sure that you’re introducing the proper amounts and types of nutrients at the correct time in the plants’ life cycle.
It’s also critical that you provide the plants with water that is pH balanced. If the pH of the water is too high or too low, you could encounter problems with your plants down the road.
Here’s a great article that covers hydroponic growing systems for beginners, and here’s one that goes more in depth about the nutrients you’ll need as your seedlings begin to grow.
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How to Germinate Your Own Pot Seeds
Hopefully all of you aspiring growers have been able to get your seeds so we can move to the next step: germination.
Take great care handling seed and seedling. Most flower and vegetable seeds are simply planted directly in the soil, but because of the value of cannabis seeds, germinating seeds prior to planting is encouraged. Growers can achieve a much higher survival rate by germinating in a non-soil medium and then transferring the seed to soil once the tap root has emerged from the seed.
Here is one of the simplest and most successful methods: Put a double layer of paper towels on a dinner plate, then thoroughly soak the towels with water and tilt the plate to drain off the excess. Place your seeds on top of the wet towels and cover with another double layer of soaked paper towels. Be sure excess water is drained off—you don’t want the seeds to be swimming.
Cover the plate with an upside-down plate or pot lid. A plastic bag or plastic wrap also works. Don’t make the seal tight—you want to leave some openings to allow air flow.
Keep the germinating seeds away from direct light. For best results, keep them at about 75 degrees Fahrenheit. A radiant heat source, like a heating pad, helps expedite the process. If you’re using a heating pad, be sure to keep the heat setting on low and place a folded hand towel between the heating pad and plate: Direct contact between the plate and heat source can cook your seeds.
Under the right conditions, seeds usually open in one to five days, so check them daily. Do not allow the towels to dry, and add water as needed to maintain moisture. Some seeds can take as long as 10 days to germinate, but if seeds have not opened within 10 days, they are not viable.
When the seeds open, the first thing to emerge is the root. Once the root sprouts it can grow quite fast.
When the root grows to a few millimeters in length, the seed is ready to be transferred to soil. Always take great care not to damage the tap root when handling. The best soil to use for a sprouting baby ganja plant is a “seed starter” or “seedling” mix. These are light neutral blends with very little fertilizer. Heavily fertilized soils will kill seedlings quickly, and cannabis seedlings prefer loose, aerated soil that their roots can easily penetrate. A bag of good starter soil is easily identifiable: When you pick it up, it should feel light and fluffy. Soils that are heavy and compact are not good for seedlings.
Now, on to potting (no pun intended). A healthy seedling will be ready for transplanting into larger container, with richer soil, in about a month. A 16- to 20-ounce container is ideal for a seedling’s first home (many growers use a Solo cup). The container must drain, so punch some holes if needed.
Fill your container with pre-moistened soil and create a hole about a half-inch deep for your seed. The tip of a pencil works well for making the right sized hole. The seed should be about a quarter-inch below the surface.
Place your germinated seed, root down, into the hole and cover lightly. Do not pack the soil on top of the seed; a light protective layer of soil is all that is needed.
Once they sprout in one to three days, new seedlings will need lots of light, and fluorescent grow light works best. Give your baby ganja plants 16 hours of light per day.
It’s very important to have a breeze on your plants immediately. A fan placed at the proper distance and speed should create a breeze just strong enough so your plant “dances,” but not so strong that it’s bent in one direction.
Without a breeze, indoor ganja plants won’t receive the stimulus needed to develop sturdy stems and branches, which the plant will need to bear the weight of big, sugary buds.
The Potanist is written by Bud Baker and Herb Green (yes, those are pseudonyms; yes, they are real people). Reach them at [email protected]
Graphics by Stephanie Rudig
Seed germination is a basic growing skill that involves causing a seed to sprout. Germinating a seed is very easy to do. This guide will explain what germination is, along with some of the most popular germination methods.
A few conditions must be present in order to properly germinate a seed. You will need proper Temperature, Moisture, Oxygen, and Darkness. There are many different methods for germinating seeds, some prefer certain methods over others, but so long as you provide the basic requirements you should succeed.
Initially, the seed absorbs water by wicking moisture through the seed coat into the seed itself. Moisture essentially brings the seed back to life. Once enough moisture has been absorbed by the seed, the exterior of the seed cracks open. At this point, the radicle emerges from the seed and forms into the root.
The hypocotyl, or stem of the germinating seed, elongates and pushes the the cotyledon above ground. The cotyledon is the part of the seed that forms into the first leaves of the seedling.
You may notice when the seed first pokes through the soil that its shape resembles a ‘shepard’s crook’. The plant does this to protect the cotyledons as they push through the soil, which is a process called skotomorphogenesis. Upon exposure to the light, phytochromes within the leaves trigger the process of de-etiolation. At this point, the ‘shepard’s crook’ will straighten (photomorphogenesis) and the plant begins to produce chlorophyll.
There are multiple germination methods to choose from. They are all easy to do, although you may find that some growers are adamant about using one method over another.
Paper Towel Method
The first germination method that I’m going to explain is called the “Paper Towel Method.” To perform the paper towel germination method, gather the following supplies:
- Container with a lid
- Paper Towels
- Seedling Heat Mat
Wet the paper towel – Don’t get it dripping wet, just thoroughly dampen it. Place the seeds on the paper towel and fold it over the seeds. Place the seeds inside of the container and close the lid. Place the container on top of the seedling heat mat or some other source of heat. Make sure the container is light proof. If it isn’t light proof, then place it in a dark area.
You don’t want it to get too hot, you want to keep the temperature between 70-80 degrees or so. If you don’t have a source of heat, that’s okay, but you can expect your seeds to germinate quicker if you provide them with elevated temperatures.
This method is widely debated, some swear by it and others swear against it. It’s a very simple germination method. You will need the following supplies:
- Cup with Distilled Water
- Seedling Heat Mat
Fill the cup with about an inch of distilled water. You can use non-distilled water, but make sure it is filtered and free of chloramines. Drop the seeds into the cup and place the cup onto your seedling heat mat. Make sure the cup is in a dark area! Light can have a negative effect on the germination process.
A heat source isn’t absolutely required, but it will help speed up the germination process. You want to raise the temperatures a few degrees above room temperature, 70 to 80 degrees is ideal.
The last method I am going to cover is called the “Rockwool Method”. This method is simple and it is advantageous in the fact that you don’t have to move your seeds once they sprout – The medium they sprout in can be transferred to soil or hydroponics for growing. Gather the following supplies for this method:
- Rockwool Cubes
- Seedling Tray with Dome
- Seedling Heat Mat
- Spray Bottle
First, before you do anything else, you need to prepare your rockwool cubes. Rockwool is known to have an unstable pH. Check our How to Prepare Rockwool Guide for more information.
Once your rockwool is prepared, poke a hole in the rockwool. Make the hole is just large enough for the seed to fit. The hole should be about 0.5” – 1.0” deep. Drop the seed down and close the top of the hole. Don’t pack the seed down in there and don’t seal the hole up too tight. Just close it enough that light can’t get in.
Try and get the taproot to face up, but if it faces down it won’t make a big difference. The plant can figure out which was it up, so it will correct itself if it isn’t facing the right direction at first. It’s one of the wonders of nature!
Make sure you adequately soak the rockwool, you want it to be pretty wet for this process to work correctly. Spray the interior of the tray and dome with the spray bottle and replace the dome. The goal here is to keep the humidity high.
The methods I covered aren’t all inclusive by any means. There are many other ways to germinate seeds that I didn’t go over. The methods mentioned above are some of the more popular methods, plus they are pretty simple and straightforward, which makes them ideal for an amateur grower.
Feel free to experiement and try different methods yourself. It’s hard to mess up germination as long as you provide the four basic requirements: Moisture, Heat, Oxygen, and Darkness. Good luck germinating and happy growing!