Can you over fertilize a plant

Signs Of Over Fertilization In Houseplants

As plants grow, they require occasional fertilizer to help sustain their overall health and vigor. Although there’s no general rule for fertilizing, as different plants have different needs, it’s a good idea to become familiar with basic houseplant fertilizer guidelines to prevent over fertilization, which can be detrimental.

Over Fertilization

Too much fertilizer can be detrimental to houseplants. Over fertilization can actually decrease growth and leave plants weak and vulnerable to pests and diseases. It can also lead to the ultimate demise of the plant. Signs of over fertilization include stunted growth, burned or dried leaf margins, wilting and collapse or death of plants. Over fertilized plants may also exhibit yellowing of the leaves.

Salt buildup, which accumulates on top of the soil, can also be a result of too much fertilizer, making it harder for plants to take up water. To alleviate

over fertilization and excess salt buildup, simply place the plant in the sink or other suitable location and thoroughly flush it out with water, repeating as needed (three to four times). Remember to allow the plant to drain well in between watering intervals.

Fertilizing only during periods of active growth and cutting the dosage will make it easier to avoid using too much fertilizer on your houseplants.

Basic Fertilizer Requirements

Most houseplants benefit from regular fertilizing during active growth. While fertilizers are available in several types (granular, liquid, tablet, and crystalline) and combinations (20-20-20, 10-5-10, etc.), all houseplants require fertilizer that contains nitrogen (N), phosphorus (P) and potassium (K). Using houseplant fertilizer in liquid form usually makes this task easier when watering plants.

However, to prevent over fertilization, it’s usually better to cut the recommended dosage on the label. Flowering plants usually require more fertilizer than others, but in small amounts. This should be done prior to blooming while the buds are still forming. Also, plants in low light will require less fertilizing than those with brighter light.

How to Fertilize

Since the fertilizer requirements vary, it can sometimes be difficult to know when or how to fertilize plants. Generally, houseplants need to be fertilized monthly during spring and summer.

Since dormant plants do not require fertilizer, you should begin to decrease the frequency and amount of fertilizer to only a couple applications once growth slows down during fall and winter. Make sure the soil is relatively moist when applying houseplant fertilizer. In fact, adding fertilizer when watering is better.

Fertilizing Vegetables

1. Q. My tomatoes are always small and the plants won’t grow very large. I think that maybe I should add more fertilizer – – even more than you recommend. Can I fertilize my plants too much?

A. Excesses of anything can cause problems. Too much water can kill trees as well as gardens – – most of us experienced the “too much” of water this spring. Too much fertilizer can also cause problems and plant death because FERTILIZER IS SALT. Why are salts toxic to many plants and most of our crops species? There are several reasons. First is that when salts are dissolved in the soil solution the plant cannot absorb and use the water it needs to survive. This is because the potential of the plant to pass water out of and into the root system must be lower than that of the soil’s holding capacity instead of the other way around. Plants can wilt when given a heavy dose of fertilizer salts. In order for the plant to adjust to salinity it must absorb and accumulate salt inside or manufacture organic solutes (sugars, organic acids, amino acids, etc.), so that the concentrations are high enough and water again can be taken up into the roots. Both of those responses require energy and take time. That’s one reason why plant growth actually slows when salts build up because of excess fertilization.

A second reason is that many salts are themselves toxic to the plant because they poison enzyme systems or block biochemical pathways. Sodium, chloride, boron, and bicarbonate are examples of specific ionic toxins which can accumulate under saline conditions.

Roots may also be injured by salts. Salt injury often makes plant roots susceptible to a wide range of soil diseases. Extreme injury may also interfere with water uptake and result in excessive wilting.

The net result of all of this is that the plant response to salt stress can be a combination of slow growth rate, and often apparent or incipient nutrient deficiency or toxicity brought on by biochemical interference. Plant injury resulting from too much salt may first be observed as yellowing of the foliage and, later, browning of leaf tips and margins.

As you can see, too much fertilizer may be fatal. The problems which you are experiencing could be the result of too much shade or variety selection.

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I am confused about miracle grow

If you have sand for soil, unless you live in a desert, it’s very possibly (but not definitely) acidic and poor in nutrients. Desert soils are often sandy and alkaline, with caliche underneath. Although Miracle Gro can add needed fertilizer and minerals, it should be noted that some nitrogen fertilizers may contribute to soil acidification (acidification can make your soil even more sandy, so I’ve read). I don’t know if your kind of Miracle Gro contributes to soil acidification, but fertilizers generally are sometimes stereotyped as leading to soil acidification over time (although only some of them do that); if soil gets too acidic, that could cause problems (see further below). This may be why some might think it could be bad to use for your purposes.

Fortunately, if your soil is too acidic, you can always add something alkaline to it, like lime, wood ash, rockdust, etc. which should help to level out the pH. Things high in calcium tend to be alkaline. You should not assume that your soil is acidic, however. Many people like to think you should always get a soil test in such situations, so as to avoid the possibility of making your soil more problematic than it was to start with (and to avoid unnecessary labor/time/costs due to error), and so you can add exactly what you need and nothing else. I’m not going to say you should always do that (since I kind of like to wing it sometimes, and learn what works for my soil by experimentation and intuition—and it’s often less expensive), but there are enough people who will disagree with my methodology that maybe you would be one of them if you knew more about the situation. So, I recommend a soil test if you can get one.

If you can’t get a soil test, don’t give up hope, but so as not to raise ire from other-minded people, I’m not going to go on about how to deal with that situation (although it is possible). With traditional methods, it takes a lot less time to raise soil pH than to lower it (so, be very careful any time you decide to try to raise the soil pH—or any time you use something with high levels of calcium in it, like lime, wood ash, rockdust, etc.)

Having a soil pH that is too acidic or too alkaline can cause nutrient deficiencies and toxicities (due to nutrients being either too available or not available enough—whether or not the nutrients are there). This can result in stunted plants, stippled foliage, yellow foliage, and other stuff.

There are many other reasons why some people might think that adding Miracle Gro is a bad idea (and no, I’m not saying it’s a bad idea by listing the reasons people sometimes have; I’m seeking to help you understand why people say what they say; I’m not trying to make you anti-Miracle Gro). I’ll list some reasons that I’ve heard.

  • It’s not approved for organic gardening. There are lots of organic gardeners out there. It contains synthetic fertilizer salts.
  • There are a lot of people who are against using phosphorus, whether because they think the soil always already has enough (whether or not it’s available), or whether they think the phosphorus industry is unethical or otherwise harmful. Miracle Gro tends to contain appreciable levels of phosphorus (but not high levels compared to other fertilizers). Another reason people are against water-soluble phosphorus is that it can leach into the ground water. Some may assume that all phosphorus is water soluble, but this is not true. However, Miracle Gro tends to be entirely water soluble.
  • It’s quick-release. Some people don’t believe in using quick-release fertilizers for some reason—probably because it doesn’t happen in nature too much). I can appreciate this rationale at least where it pertains to acclimatization (where people are trying to breed plants that are not reliant on such fertilizers, as Joseph Lofthouse does with landraces—he raises plants without fertilizer and *cides—not particularly just quick-release).
  • Using too much Miracle Gro may result in ‘salty’ soil. Salty doesn’t refer specifically to sodium, by the way. A salt is a mineral or element that is bound to an acid. For instance, magnesium malate is a salt that people use for supplementing magnesium in humans (malate comes from malic acid, and magnesium is the mineral). Some people worry a lot about using too many fertilizer salts (since if soil is too salty, it is said to cause issues for plants).
  • It’s easy to burn plants with Miracle Gro. Some people don’t like to risk burning plants. But, if you follow the directions, you shouldn’t normally burn any plants (although it is possible). Be sure to research the salt index. Different fertilizer salts have different indexes. The higher the index, the greater the likelihood of plants being burned. I’ve personally found it easy to burn indoor pre-transplant vegetables with 24-8-16 Miracle Gro, but I don’t think I’ve ever burned an outdoor plant or a houseplant with it (it works great for houseplants, in my experience). They make kinds that are more suited for vegetables, and I’ve used one for tomatoes (but it’s not my favorite for pre-transplant tomatoes; I haven’t tried it outdoors).
  • I don’t know all of the Miracle Gro products do, but some fertilizers kill some soil microbes, and a lot of people probably assume that Miracle Gro does by default. I know calcium nitrate, and potassium chloride, are said to kill soil microbes. I don’t know about other fertilizer salts (other than at least some nitrates), however, and I don’t know if Miracle Gro contains nitrates or potassium chloride (but it’s a good possibility). Edit: My 24-8-16 All Purpose Plant Food (years old) contains potassium chloride, but no nitrates. Some people think urea kills soil life, but I haven’t been able to verify whether this is true or false; it would seem to stimulate it if anything, from what I know about it.
  • Some may think it’s unhealthy. This may in some cases be because of reactions they or others have to certain fertilizer ingredients. Or, they may worry about fluoride, plthalates, lead, and other stuff, whether or not they’re in Miracle Gro (they are in some fertilizers).

Also, realize that desert soils may be high in water soluble salts already (although in a 40-year-old garden I’m more doubtful of that); so, if you do have alkaline, sandy soil, you’d potentially have to worry about the salts in your fertilizer, even if the acidification isn’t a concern. You’d probably want a soil test to find what, if anything, you need.

7 Signs You’re Over-Fertilizing Your Houseplant & How to Fix It

You know that plants need fertilizer to get all the nutrients they need to be healthy, but can you have too much of a good thing?

You sure can!

In human health, we tend to worry a lot about vitamin and mineral deficiencies, but an excess of vital nutrients can be just as harmful. For example, too much vitamin A can make you very sick. Kidney stones are caused by mineral imbalances.

Excessive fertilizer can harm plants, so it’s important to keep the balance right!

What can too much fertilizer do to plants?

So what are the dangers of over-fertilizing plants?

The main danger is “burning” caused by too much fertilizer. Fertilizers have high amounts of different salts that can pull moisture away from the roots in a process called reverse osmosis.

If the salt content in the soil is higher than what the plant contains, then reverse osmosis will occur and the plant will be in danger of chemical burns and dehydration.

The most severe damage occurs underground in the roots where the soil is. Excess salt in fertilizers can “burn” the roots and limit moisture uptake.

And if the plant can’t absorb water, it’s in trouble!

We obviously don’t want that, so let’s look at the signs that your plant is getting too much fertilizer.

7 signs your houseplants are over-fertilized

A crust of fertilizer on the soil surface

This is a sign that the plant is not absorbing the minerals, so they’re building up on the surface of the soil.

Yellowing and wilting of lower leaves

This can also be caused by overwatering or not enough light, so do a little experimenting to determine the exact cause. Watch for the other signs on this list as well!

Browning leaf tips and margins

This can indicate that the plant isn’t absorbing water properly, which is a symptom of over-fertilizing.

Limp and browned or blackened roots

This is a sign of the “burning” we mentioned earlier.


Watch for falling leaves. This can also be caused by improper watering, so take that into consideration as well.

Lack of blossoms

Should your plant be blossoming by now? If it’s not, something is off.

Very slow or no growth

Plants need the right balance of nutrients to support growth and metabolism, so if you’re not seeing progress, that’s a good sign that the nutrients are imbalanced.

Rescue mission: How to reverse over-fertilization of your houseplant

Your plant is showing the signs above, and you’ve determined that it’s receiving too much fertilizer. Is this the end?

Don’t panic! All your plant needs is a little extra love and attention to get back into balance.

The first thing you want to do is remove as much excess fertilizer as possible.

If there is a crust of fertilizer on the surface of the soil, use a spoon to remove it carefully, but don’t take more than ¼ of soil with it. We don’t want to stress the plant any more than it already is.

Next, remove the wilted or and burned leaves.

After that, leach the fertilizer out of the soil with a nice, long watering. Let the water run out of the drainage holes and empty the trays immediately. You might want to do this three or four times, because this will take the fertilizer out of the roots.

After leaching, don’t fertilize the plant for at least a month.

Your plant should perk up and start growing again soon!

Comparative Effects of Different Fertilizer Sources on the Growth and Nutrient Content of Moringa (Moringa oleifera) Seedling in a Greenhouse Trial


A greenhouse experiment was conducted to investigate the effects of NPK, poultry manure, and organomineral fertilizer on the growth and nutrient concentration of Moringa oleifera leaves. The experimental design was completely randomized design (CRD) with four treatments replicated three times. Data collected were analysed using descriptive statistics and ANOVA at . Growth parameters measured include number of leaves per plant, plant height (cm), and stem girth (mm). The application of poultry manure increased the height, number of leaves, and stem girth of moringa compared to the application of NPK and organomineral fertilizer while the control had the least growth. Poultry manure, NPK, and organomineral fertilizer were 66%, 62%, and 39% higher in number of leaves than the control at eight weeks after planting. The application of poultry manure significantly increased the nutrient content of moringa leaves compared to other sources of fertilizer applied. The results shows that the application of poultry manure significantly improved the growth and nutrient content of moringa; however, further field trial is suggested.

1. Introduction

Moringa oleifera originated from the foothills of the Himalayas in Northwestern India and is cultivated throughout the tropics . Moringa can be cultivated in a wide range of soil types but grow best in well-drained loam to clay loam soil with slightly acidic to neutral pH however, it cannot withstand prolonged water logging. Moringa is very useful in the following areas; as alley cropping, animal forage, biogas, domestic cleaning agent, green manure, gum, medicine, ornamental plants, and water purification. Moringa leaves, seeds, and roots are also use in treating diseases like lung diseases, hypertension and skin infection .

Moringa is nutritional and rich in vitamins and minerals. Moringa leaves are the most nutritious part of the plant, being a significant source of vitamin B6 vitamin C, and provitamin A as beta carotene, magnesium, and calcium . However, Moringa still remains unpopular in Nigeria despite its acclaimed economic values and importance; very little research has been done on this plant, although it is widely used by the rural poor as a food resource .

Land degrading is one of the major impediments to agricultural productivity. This is manifested in the loss of soil fertility, desertification, and destruction of the soil structure . Due to the implication of land degradation on agronomic productivity and the environment, it becomes necessary to proffer means to minimize it effects. Ultisols of tropical and subtropical regions occur in old landscapes that have a monsoon climate and are extremely weathered and leached. They have a red, brown, or yellow argillic B horizon with a base saturation of less than 50%. The soils have a low content of organic matter with ferric and hydromorphic properties. These soils are generally of low fertility and are susceptible to erosion . One way to improve soil fertility is the application of fertilizer which obviously is a means required for optimum crop yield.

The use of poultry dungs has been documented to give a better result on soil amendment in degraded ultisols . It has been reported that organic manure can serve as soil amendment to improve soil nutrient status and the growth of crops . Organic base fertilizer such as organomineral fertilizer improves soil structure, reduces erosion, lowers the temperature at the soil surface, and increases soil water holding capacity . The use of NPK fertilizer has resulted in the improvement of the growth and yield of crops. Due to increasing demand of moringa for biofuel and medicinal uses, it is therefore necessary to investigate ways to improve its growth in degraded soil. This study aimed at the responses of moringa seedling to soil amendment in degraded ultisols of Edo state under a greenhouse condition.

2. Materials and Methods

2.1. Description of Experimental Site

The experiment was conducted at the Teaching and Research Farm of Ambrose Alli University, Emaudo Annex, Ekpoma, in 2012 under greenhouse condition. The area lies between latitude North 6 degrees, 45 minutes, 34 seconds (6° 45′ 34′′) and longitude East 6 degrees, 8 minutes, 27 seconds (6° 8′ 27′′ East) with average amount of rainfall 1750 mm.

2.2. Collection of Soil for Analysis

Top soils (0–15 cm) were collected from the farm site; the soils were sieved with a 2 mm mesh to remove gravel and plant roots. The 5 kg polythene bags used for the experiment were filled with the sieved soil.

2.3. Soil Physical and Chemical Analysis

Particle size analysis was carried out using hydrometer method . The pH was determined in water (ratio 1 : 1, soil : water). Organic carbon was determined by wet dichromate method and available phosphorus by Bray extraction method . Total nitrogen was determined by Kjeldahl method. Exchangeable cations (potassium, calcium, and magnesium) were extracted with ammonium acetate. Potassium was determined by flame photometer while calcium and magnesium were determined by atomic absorption spectrophotometer. Copper, zinc, manganese, and iron were also determined .

2.4. Experimental Design

The experimental design was a completely randomized design (CRD) with four treatments replicated three times. The treatments were NKP, organomineral fertilizer (OMF), poultry manure, and control.

2.5. Planting Operation

Moringa (Moringa Oleifera) seeds were first soaked in water for 24 hours to allow the seeds to absorb the moisture required for sprouting. The seeds were removed from the water, wrapped in a wet towel, and stored in a warm dark place. The towel was kept damp to allow maximum germination and prevent drought. The sprouted seeds were planted two per pot and later thinned to one stand per pot.

2.6. Fertilizer Application

Poultry manure (PM) was applied four weeks before planting at the rate of 100 g per pot; organomineral fertilizer (OMF) was applied two weeks before planting at the rate of 5 g per pot. NPK fertilizer was applied two weeks after planting at the rate of 2 g per pot. Ring application method was used for NPK and OMF while poultry manure was mixed with the soil.

2.7. Spacing

The pots were arranged at a distance of 60 cm × 60 cm between and within rows. A total number of 12 pots were used for the experiment.

2.8. Collection of Data

Growth parameters such as plant height, number of leaves, and stem girth were measured at 4, 6, and 8 weeks after planting the sprouted seeds. Moringa leaves were collected for plant nutrient analysis at eight weeks after planting.

3. Results

Table 1 Physicochemical properties of soil before planting.

3.1. The Chemical Properties of the Poultry Manure Used for the Experiment

Table 2 Nutrient content of poultry manure.

3.2. Organomineral Fertilizer Analysis

Table 3 Nutrient content of organomineral fertilizer grade A.

3.3. Growth Parameter of Moringa
3.3.1. Plant Height (cm)

Poultry manure consistently and significantly increased the height of moringa compared to other treatments. At six weeks after planting, the height of moringa was significantly () increased with the application of poultry manure (52.8 cm) compared to the application of NPK, organomineral fertilizer. Also at eight weeks after planting, application of poultry manure significantly () increased the height of moringa (65.47 cm) compared to other treatments (Table 4).

Treatment Week after sprouting
4 6 8
Control 14.50b 25.00b 27.50b
OMF 22.40a 22.70b 27.95b
NPK 22.53a 48.47a 59.00a
Poultry manure 28.10a 52.80a 65.47a
Values followed by different letters under the same column are significantly different using Duncan’s multiple range test ().

Table 4 Responses of moringa height (cm) to different fertilizer applications.

3.3.2. Stem Girth (mm)

The stem girth of moringa was not significantly different among treatments at four weeks after planting. However, the application of poultry manure and NPK significantly () increased the stem girth of moringa (7.22 mm and 6.90 mm) compared to the application of OMF and control. At eight weeks after planting, the stem girth of moringa was significantly () higher when poultry manure and NPK were applied (8.83 mm and 8.16 mm) compared to OMF application and control (Table 5).

Treatment Week after sprouting
4 6 8
Control 2.93a 4.76b 5.04b
OMF 3.20a 3.88b 4.62b
NPK 3.16a 6.90a 8.16a
Poultry manure 3.46a 7.22a 8.83a
Values followed by different letters under the same column are significantly different using Duncan’s multiple range test ().

Table 5 Responses of moringa stem girth (mm) to different fertilizer applications.

3.3.3. Number of Leaves

Application of fertilizer did not significantly () increase the number of leaves of moringa at four weeks after planting. However, at six weeks after planting, the application of poultry manure and NPK significantly () increased the number of leaves of moringa (334.33 and 307.007) compared to OMF and the control. It was observed that, at eight weeks after planting, poultry manure significantly () increased the number of leaves of moringa (378.33) compared to other treatments (Table 6).

Treatment Week after sprouting
4 6 8
Control 81.00a 119.00b 127.00c
OMF 64.50a 135.00b 209.50b
NPK 99.00a 307.00a 336.00b
Poultry manure 102.66a 334.33a 378.33a
Values followed by different letters under the same column are significantly different using Duncan’s multiple range test ().

Table 6 Responses of number of leaves of moringa to different fertilizer applications.

3.3.4. Nutrient Content of Moringa Oleifera Leaves

Nutrient content of Moringa oleifera leaves was significantly () influenced by fertilizer application. Poultry manure and NPK significantly () increased the nitrogen content of moringa leaves. Phosphorus, potassium, sodium, and manganese content in moringa leaves were significantly () higher with the application of poultry manure compared to other treatments. OMF application had the highest calcium content with value 2.46 cmol/kg. NPK application increased the values of Cu and Fe content in the leaves of moringa while the control has higher magnesium and zinc (Zn) content compared to other treatments (Table 7).

Table 7 Comparative effect of PM, OMF, and NPK on the nutrient content of moringa.

3.3.5. Correlation Analysis

Positive correlation exists between phosphorus and potassium content at 0.07% and phosphorus and sodium at 0.01%. The result showed that as phosphorus increases potassium and sodium increases as well. It was also observed that there was positive correlation between the following nutrient elements: nitrogen and iron, calcium and iron, and nitrogen and copper, and between magnesium and zinc at 0.01%. The result shows that as nitrogen and calcium increased, iron content increased correspondingly (Table 8).

Table 8 Correlation Analysis.

4. Discussion

The major limiting factor of crop production in the tropics is the deficiency of soil nutrient resulting from land degradation which affects the growth, nutrient content, and uptake of the plant. Low levels of nitrogen, phosphorus, and organic carbon were observed in the soil used for the experiment and the finding corroborates with the earlier results ; they reported that most of Nigerian soil is deficient in nitrogen, phosphorus, and potassium even organic matter. Therefore, a sustainable method of improving the nutritional status of the soil should be employed to enhance the growth and nutrient content of the plant.

The application of NPK (15 : 15 : 15) fertilizer significantly increased the vegetative growth of moringa plant and this finding agreed with earlier work done . It was reported that the application of NPK fertilizer significantly () increased the vegetative growth of moringa which was also observed from the experiment .

The application of poultry manure significantly () increased the height, stem girth, and number of leaves (vegetative growth) of moringa. This result corresponded to the earlier finding . It was reported that the application of poultry manure significantly () increased vegetative growth of moringa. This could result from the nutritional benefits of poultry manure which include improvement of soil fertility, structure, water holding capacity, and organic matter. This will reduce the amount of inorganic fertilizers needed for the growth of moringa plant . The effect of compost and other organic amendment on the growth of moringa plant may be the result of the interaction between the nutrient present and growth of moringa, as organic manure has been found to contain auxins, gibberellins, and cytokines .

The application of fertilizer significantly () increased the nutrient content of moringa. Poultry manure application increased the P, K, Na, and Mn content of moringa and this result corresponded to earlier work done . It has been reported that the application of organic manure increased the nutrient concentration of arable and other crops . Similarly, NPK application also improved the nutrient content of moringa which has earlier been reported . The improvement of calcium, potassium, and sodium content of moringa by the application of OMF agreed with the work earlier done . It was reported that organic base fertilizer (OMF) improved the nutrient content of arable crops.

5. Conclusion

The comparative effects of NPK, poultry manure, and OMF on growth of moringa seedling and nutrient concentration was investigated. The results of this study show that the application of poultry manure significantly increased the vegetative growth of moringa. Also the nutrient concentration on the leaves of moringa was significantly improved by amending degraded soil with poultry manure. These results can be investigated further on a field trial.

Conflict of Interests

The authors declared no conflicting interests regarding the publication of this paper.

Feeding plants

About plant nutrients

Most plants need three major nutrients to thrive; nitrogen, phosphorous and potassium, which are generally known as NPK (their chemical symbols). The three main nutrients are needed by plants for different reasons. Nitrogen promotes leaf growth, phosphorous is for the roots and potassium is needed for flower and fruits. The amount of each is written on fertiliser packets as a ratio, for instance 6:4:6. Note that the order of nutrients is always the same, ie N, P, K. If the ratios are about the same, it is a general-purpose fertiliser and will aid all round growth, but some fertilisers are higher in one or another nutirent. For instance, tomato fertiliser is designed to promote lots of plump fruit and will be high in potassium (K) and have a ratio of 4:5:8. Similarly a fertiliser for feeding grass in the spring will be high in nitrogen.

What to do

When to feed

  • Give beds and borders a kick start by feeding in spring with a slow release fertiliser, before plants have put on too much growth. This is known as top dressing. Fertiliser applied to the soil and worked in prior to sowing or planting is called base dressing.
  • Vegetables are hungry crops and will thrive if given a slow-release fertiliser two or three times a year.
  • Other ‘greedy’ flowering plants, such as sweet peas, clematis and roses, will benefit from a mid-summer ‘top up’. Sprinkle fertiliser around plants and water in. There’s no need to feed in late summer. This only encourages a flush of late, lush growth that’ll get hit hard by frosts.
  • During the growing season, feed flowers in hanging baskets, pots and containers once a week, using a liquid feed applied from a watering can.

Improving soil

  • Apart from providing fertilisers to the soil, it’s a good idea to enrich soil before planting by adding plenty of organic matter, such as leafmould, garden compost or well-rotted manure. Not only will this boost the nutrient content of the soil, but it will improve its structure and help it to retain moisture.
  • To do this spread a thick (about 5cm (2in) will do) layer of the material over the soil and fork into the surface to a depth of about 10cm (4in). To give existing beds a boost, mulch around plants with organic matter in the spring.

Different fertilisers

There are many different types of fertiliser available, including liquid tonics that can be applied from a watering can, granular fertilisers that are mixed into compost and powdered feed that is applied to the soil. These feeds work in three main ways:

  • Controlled release fertiliser – ideal for containers, these come as granules that are mixed into compost and release their nutrients over a long period of time, some for up to 12 months. Plugs made from granules bonded together are also available – these can simply be pushed into the surface of the compost.
  • Slow release fertiliser – good for feeding plants in the soil. Usually applied as a powder that can be scattered around perennials, trees, shrubs and vegetables.
  • Fast acting fertiliser – for plants in need of a pick-me-up. These are ideal if a plant is suffering from a deficiency and are usually applied in a liquid form that can be used by the plant quickly.

Seaweed fertilizers are a good organic option. Alternatively try diluting the liquid from a worm composter.


  • Always read the manufacturers instructions before applying fertilisers
  • Don’t overfeed plants
  • Wear gloves if handling powder or granular fertilisers
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