Tomato Seed Starting Tips
- Purchase and Prepare Your Tomato Seed
- Select Your Tomato Seed Containers:
- Decide When to Start Your Tomato Seeds:
- Planting Your Tomato Seeds:
- Wait for Germination:
- Give Your Seedlings Light:
- How to germinate seeds to get best results when growing tomatoes from seeds
- Before you leave …
- Planting Tomato Seeds – How To Start Tomato Plants From Seed
- When to Start Tomato Seeds
- How to Start Tomato Plants from Seed
Purchase and Prepare Your Tomato Seed
Because your garden soil compacts too easily and can harbor organisms that may cause diseases it’s a better choice to purchase a prepared seed starting mix. A good commercial seed starting mix is often a blend of peat moss, vermiculite and perlite.
I like to thoroughly combine the seed starting mix with warm water to make it useable since a dry mix is difficult to work with. You may want to let your seed starting mix sit wet overnight before using to assure that it is evenly soaked. The final product should be evenly dampened but not soggy wet.
Select Your Tomato Seed Containers:
As long as your tomato seeds get sufficient moisture, warmth and drainage almost any container will work. I used to use styrofoam cups with holes punched in the bottom. I’ve found that commercially available seed starting kits with peat or plastic containers are easy to use and proven successful. Most gardening stores will carry seed starting containers with single or multiple cells. I now use commercially available 128 cell seed trays.
If you choose to reuse older plastic containers, I suggest sterilizing them first with a light bleach solution (5-10%)
Your choice of the container that will best fit your needs depends upon how many plants you wish to start.
Decide When to Start Your Tomato Seeds:
Avoid planting too early to prevent plants from becoming root-bound or spindly. Sow your certified tomato seeds 6-8 weeks before planting your seedlings outdoors. Planting your seedlings outdoors should be scheduled around 2 weeks following the average last frost date for your region. Check the climate zone map on TomatoFest or ask your local nursery, or gardening friends for the best date for you to plant.
Planting Your Tomato Seeds:
I advise planting 20% more seeds than the number of plants you’ll want to allow for seeds that may not germinate or seedlings that become damaged. It’s generally pretty easy to find a home for seedlings you won’t be using. Fill container with dampened seed starting mix. Tamp down mix to get air out. Plant your seeds a maximum of 1/4 inch deep. Then tamp down mix again lightly. Dampen soil mix thoroughly with a gentle drizzling of water.
Put your containers or tray into a loose-fitting plastic bag (leaving the end open for circulation. Some air circulation is good but don’t let the mix dry out because dry seeds won’t germinate.
Wait for Germination:
This is the hard part. Be patient. Place your containers in a warm location out of direct sunlight. Light is ok, but not needed during the germination process.
If temperature is kept consistently and sufficiently warm, your tomato seeds will usually germinate within 5 to 10 days. Best to keep temperature range 70 to 80F (21 to 27C). The lower the temperature the slower the germination. However, temperatures below 50F (10C) or above 95F (35C) are poor for germination. (Some varieties need more time to germinate.) When seeds start coming up remove tray from plastic bag.
Watch for the first seedlings, because they will need to be moved into a good light source as soon as they begin to emerge from the soil. If the light is not adequate, you will get long, leggy stems shooting up which is not good.
Give Your Seedlings Light:
Many home gardeners use windowsills. The light your seedlings receive on a windowsill may be adequate but most often is insufficient and may lead to leggy growth as a result of seedlings stretching for sunlight. If you have no other light source than a windowsill, turn your seedlings regularly. For ideal growth, set up full spectrum grow lights or white florescent lights just a few inches above the seedlings. Be creative to find a way to get your seedlings directly under the lights.
Remember, strong light is needed to support tomato growth. Your lights should stay on for 14 to 16 hours per day.
How to germinate seeds to get best results when growing tomatoes from seeds
Germinate seeds before you sow them in potting mix. Pre-sprouting helps accelerate your tomato seedling crop.
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Pre-sprouting is easy. It takes just a couple of days.
When you germinate tomato seeds before planting them, they have a greater chance of growing into seedlings than those you sow directly.
You’ll give your seeds a jump start on the growing season.
Plus, you’ll get more plants from the same amount of seeds that you sow directly into your indoor pots.
What you need
- tomato seeds
- paper towel or paper napkin
- ziploc sandwich bags
- marker to label bags
- seedling heat mat
What to do
- Moisten a single paper towel sheet or paper napkin. Paper should be damp but not sopping wet.
- Sprinkle tomato seeds on paper towel so they are not touching. Seeds will adhere to paper. Use only one variety of tomato seed per roll. If you’d like to pre-sprout just a few seeds of one variety, tear the paper towel into smaller sections.
- Starting at one end, roll the paper towel or napkin loosely in cylinder-fashion.
- Place the rolled paper towel into a zipped plastic bag.
- Label the bag with tomato variety and date.
- Place bag in a warm place away from drafts, such as on the top of the refrigerator or stereo. Or use a seedling heat mat.
- Check the seeds a couple of times each day for germination. Carefully unroll the paper cylinder and look for the root emerging from the seed. Some seeds germinate within 24-48 hours. Other varieties, especially smaller varieties and those suited to grow in containers, take longer to sprout – as much as 10-14 days.
- As soon as the seed’s tap root emerges, plant your germinated seeds.
- Plant your germinated seeds in seed cell trays within 12-24 hours of sprouting. Be careful to not allow the seed’s root to grow too long while still in the paper towel, or the root will penetrate the paper and be difficult to manipulate without breakage. Once the root is broken, your seed will no longer be viable.
Video: How to Germinate Tomato Seeds Before Planting
Seed starting containers to use when you sow tomatoes
Seed starting mix for tomatoes: what ingredients are important …
Can I germinate old tomato seeds?
What potting mix to use when starting tomato seeds …
Review: Pro-Mix Seed Starting Formula for growing tomato seeds …
Tomato seed starting timetable …
How to label and grow tomatoes from seed
Tomato growing tips for seeds …
Learn what tomato seedlings need after they germinate …
How to grow tomatoes from seeds – is it really hard to do?
Tomato varieties, heirloom tomatoes, hybrids …
How to plant tomato seeds …
Re-potting tomato seedlings to a bigger container …
Strengthen a growing tomato plant to prepare it for the home garden
Return from Germinate Seeds to Tomato Dirt home
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1. Starting indoors, in a container of well moistened, sterile seed-starting mix, make shallow furrows with a pencil or chopstick about 1/4 in. deep. Sow seeds by dropping them along the bottom of the furrows 1/2 in. apart.
2. Gently pinch together soil to cover each furrow, covering seeds 1/4 in. deep. Water gently and label each variety. Put container in a warm place, 75-80˚ F. As soon as seed begin germinating and stems start to show above the soil, it’s critical to provide a strong light source such as fluorescent bulbs or a very sunny window.
3. Day 7 – Seedlings have germinated. First to appear are “baby” or “cotyledon” leaves. Careful labeling of each variety is important as they all look alike.
4. Day 15 – Seedlings are still tiny with just baby cotyledon leaves, but growing well. Note the nice green color of the baby leaves. This indicates that plants are getting enough bright light to thrive.
5. Day 30 – The first set of “true” tomato leaves begin to appear above the baby cotyledon leaves. The best example of this is in front of the pencil eraser in this picture.
6. Now that true leaves have emerged on all the seedlings, it’s time to transplant seedlings to larger individual containers so they have enough room to properly grow and develop. This process is called “pricking out” the seedlings.
7. To “prick out:” lift seedlings from below, holding each one gently by their baby cotyledon leaves and scooping up entire soil ball from below. We find an old fork works well for this.
8. If roots have grown together into a clump, gently tease seedlings apart, holding by baby cotyledon leaves.
9. Transplant each seedling into its own container (at least 3-4 in. in diameter) filled with good quality, well moistened potting mix. Make a hole to receive each seedling.
10. Insert each seedling into the hole to the base of its cotyledon leaves.
11. Tomato seedlings will readily grow new roots along their buried stems and the resulting plants will be sturdy and vigorous. Gently water in the seedlings to settle the plants.
12. Here are examples of what healthy and cold stressed seedling look like. Remember that seedlings need to be kept at about 65 – 70 degrees after they have true leaves and until they are ready to go into the garden.
13. When spring weather has warmed up and night temperatures are regularly in the 55 degree range, it’s time to plant well rooted, established seedlings outdoors. First plan to acclimate your plants: move them outside into the sun, first for a few hours , then gradually increasing over a weeks’ time until they are in full sun all day. This process is called “hardening off” and it avoids transplant shock.
14. At transplanting time, if hardened off young plants are more than 6 in. tall, remove the bottom branches before planting. New roots will form along the buried stem.
15. Prepare the hole to receive the seedling.
16. Tip out plant by overturning pot to squeeze or tap out the entire root ball. Note the snipped off lower branches on this example ready to go into the ground.
17. Settle the seedling into the hole, so the entire stem will be covered up to where leafy branches begin. Pull soil around the plant and firm.
18. Water gently but thoroughly and erect your tomato supports. Be sure they are well secured, because your plants will grow large and heavy with fruit, so you will need strong support for the branches.
19. Enjoy the harvest! For heirloom varieties like our Rainbow’s End, it’s best to wait for full ripeness before picking the luscious, color fruit.
20. Slicers, like Crimson Carmello or Chianti Rose can be harvested at any stage you like them.
21. Don’t forget your sauce tomatoes. Here’s a bowl of our variety Pompeii all ready to put up. We like to freeze them whole, then make sauce later when the weather is cold and miserable, and making big pots of tomato sauce is fragrant fun.
22. Heirloom Camp Joy cherry tomatoes are very prolific and delicious.
23. Garden Candy Cherries are beautiful in the garden and kitchen.
24. Big Beef beefsteak giant slicers are heavy with sweet flesh and lots of juice – perfect for open-faced “BLT” sandwiches.
Nothing is more gratifying than a big tomato harvest in the summer season!
The tomato is the most popular warm-season crop, but it can be surprisingly tricky to tend to full productive glory. Tomatoes require at least 6 hours of full sun per day, are fertilizer and water hogs, and produce fruit most vigorously when days are warm (between 78 and 92 degrees Fahrenheit) and nights moderately warm (at least 70 degrees Fahrenheit). Vining (indeterminate) types need caging or trellising, while bush (determinant) types may or may not need staking; both benefit from seasonal pruning. For temperate growers, late winter is the best time to plant homegrown tomato plants from seed for spring planting.
‘Gold Medal’ is one of the best-tasting and prettiest beefsteak tomatoes.
These savory fruits come in all colors, shapes, and sizes and flavor is surprisingly variable. In my garden I always choose several slicers, sauce tomatoes, salad tomatoes, and cherries each year. This year’s pickings include the heirloom red and yellow slicer ‘Gold Medal‘, the French salad tomato ‘Crimson Carmello‘, and orange beefsteak ‘Kellogg’s Orange Breakfast‘. My favorite sauce tomatoes are the Italian powerhouses ‘Pomodoro‘, ‘San Marzano Redorta‘ as well as the salad-sized ‘Principe Borghese‘, which is touted as the best tomato for sun drying. My cherry tomatoes of choice are the sweet, golden ‘Sun Gold‘, tiny red ‘Matt’s Wild Cherry‘ and delectable yellow and red ‘Isis Candy‘. All are beautiful and have exceptional flavor. Here are the basics for starting, growing, protecting, and harvesting your tomatoes for success and high yields.
- Common Name: Tomato
- Botanical Name: Lycopersicon esculentum (syn. Solanum lycopersicum var. lycopersicum)
- Days to Harvest: 65 to 85 days after planting
- Soil: Rich, porous, friable loam amended with Black Gold Garden Compost
- Common Problems: Tomato hornworms, damping off caused by Pythium and Phytophthora pathogenic fungi, cool temperatures (causes fruit toughness, cat-facing, and reduced productivity), Colorado potato beetles, and blossom end rot (a physiological disorder caused by calcium deficiency), splitting/cracking (happens to mature or nearly mature fruits on the vine when plants get excessive water or temperatures dramatically fluctuate.)
- Planting Time: After the last frost date, in temperate zones; in warmer climes, they can be planted at any time of year as long as temperatures are warm enough
- Fertilization: Feed at planting time with an organic fertilizer formulated for tomatoes, as these always contain sufficient calcium.
Days to Harvest Timeline
‘Pomodoro’ is a fantastic all-purpose tomato for fresh eating and cooking.
Starting Seeds: It takes around six to eight weeks to grow tomatoes from seed to plantable seedlings. Start seeds indoors for best results. In 5 to 12 days your tomato seeds should germinate. Germination is best in warm temperatures (68° to 75° Fahrenheit (20-24° Celcius)). A heat mat for seed starting will dramatically hasten tomato seed germination. Sow seeds in cells filled with seedling mix and lightly sprinkle a bit on top to cover. Gently moisten the cells with water and place right under the warmth of grow lights. (.)
Tending Seedlings: Tomato seedlings are very delicate and have two lance-shaped seed leaves. True leaves start to appear in 2 to 3 days. Continue to keep plants lightly moist and feed with a diluted all-purpose fertilizer, once the seed leaves have appeared. To avoid leaf burn, lift grow lights up as seed leaves get closer to the bulbs. (*Grower’s warning: Don’t allow soil to become too saturated. Wet soil can encourage fungal disease and cause seedlings to rot or “damp off.”)
Tending Small Plants: Tomato plants should be around 8 to 10 inches tall after 42 to 56 days and garden ready. Before planting outdoors, plantlets need to be hardened off for at least a week. Hardening off means acclimating seedlings from their cushy indoor growing conditions to the windy, sunny outdoors where temperatures fluctuate greatly. Indoor grown seedlings are very tender, have weak stems and need time to adjust to full sun. If directly planted outdoors they will fry.
To harden them off, place your potted plantlets in a protected spot that gets a few hours of sun per day. Check them daily and slowly place them in a location where they get a little more light each day. After a week of so, they should be ready to plant in the garden.
‘Matt’s Wild Cherry’ is a delicious, tiny cherry tomato with big flavor.
Garden Planting: Amend planting beds by digging and turning the soil deeply and adding rich compost and an OMRI-Listed tomato and vegetable fertilizer. Plant tomatoes around 4 feet apart and mulch with a 2 to 3 inch layer of compost. Young plants can be planted deep, with only a couple of nodes with foliage above ground, but leaves should be gently removed from all stem parts that will be covered with soil. Indeterminate tomatoes should be fitted with a sizable tomato cage right away to support vines and fruits as plants develop. Water regularly to keep plants moist, not wet. Days to harvest vary, but plants usually begin to bear fruit 65 to 85 days after planting.
Container Planting: Tomatoes are such aggressive feeders and water hounds, you have to give serious attention to container grown plants. Start with a really large pot. Determinant tomatoes are best, but indeterminant tomatoes will also work if you keep them caged and pruned. A good organic water-holding potting soil is perfect for container culture. I recommend Sunshine® Advanced Rain Forest Blend 0.06-0.02-0.05, which also contains Resilience™ for stronger stems, more compact growth & better root development. Container-grown tomatoes need to be watered daily and fed more frequently, but if you give them ample attention, they should thrive and produce beautifully.
Harvest: Tomatoes can be harvested green for fried green tomatoes and green tomato chutney, but they are best picked fully colored and ripe. Some tomatoes are naturally easy to pull from the vine when mature, while others cling to the vine. I always keep a pair of harvest sheers on hand for clingers. If you accidentally harvest a few fruits with a bit of green, let them stand on a sunny window for a couple of days, and they will ripen up right away.
Pruning: Tomatoes can be cut back and shaped to keep them from overtaking a trellis or container. Use sharp, clean pruners to cut whole branches back to main stems as needed. Try to maintain productive, fruit and flower laden branches, if at all possible. As a precautionary measure, it is wise to dip pruners in a 10% bleach solution when pruning from plant to plant, just to avoid the possibility of spreading disease. Dip and wipe the pruners after pruning one plant and going to another.
Preparation: This is the easy part. Lavish burgers with big, hearty tomato slices, eat them fresh in salads or make homemade tomato sauce and salsa. To extend the season, freeze whole tomatoes and sauce for winter. (This generally requires at least 10 healthy tomato plants to provide enough to store all winter.)
Growing tomatoes is gratifying if you follow the proper steps and give them the best care. If you do it right you should have more than enough tomatoes to enjoy and share. I wish you the best tomato season!
Follow these instructions and you’ll have enough tomatoes for storing and sharing with friends.
Planting Tomato Seeds – How To Start Tomato Plants From Seed
Growing tomatoes from seed can open a whole new world of specialty, heirloom or unusual tomatoes. While your local nursery may only sell a dozen or two tomato varieties as plants, there are literally hundreds of tomato varieties available as seeds. Starting tomato plants from seeds is easy and requires only a little bit of planning. Let’s take a look at how to start tomato plants from seed.
When to Start Tomato Seeds
The best time to start tomato plants from seeds is about six to eight weeks before you plan on planting them out into your garden. For areas that get frost, plan on planting out your tomato seedlings two to three weeks after your last frost, so you will start growing tomatoes from seed at four to six weeks before your last frost date.
How to Start Tomato Plants from Seed
Tomato seeds can be started in small pots of damp seed starting soil, damp potting soil or in moistened peat pellets. In each container, you will be planting two tomato seeds. This will help ensure that each container will have a tomato seedling, in case some of the tomato seeds do not germinate.
The tomato seeds should be planted about three times deeper than the size of the seed. This will be about 1/8 to 1/4 of an inch, depending on the tomato variety that you have chosen to grow.
After the tomato seeds have been planted, place the seedling containers in a warm place. For fastest germination, temperatures of 70-80 F. (21-27 C.) are best. Bottom heat will also help. Many gardeners find that placing the planted tomato seed containers on the top of the refrigerator or other appliance that generates heat from running works very well for germination. A heating pad on low covered with a towel will also work.
After planting the tomato seeds, it is just a matter of waiting for the seeds to germinate. The tomato seeds should germinate in one to two weeks. Cooler temperatures will result in a longer germination time and warmer temperatures will make the tomato seeds germinate faster.
Once the tomato seeds have germinated, you can take the tomato seedlings off the heat source, but they should still be kept somewhere warm. The tomato seedlings will need bright light and the soil should be kept moist. Watering from below is best, but if this is not possible, water the tomato seedlings so that water does not fall on the new sprouts. A bright south-facing window will work for light, or a fluorescent or grow bulb placed a few inches above the tomato seedlings will also work.
Once the tomato seedlings have a set of true leaves, you can give them quarter strength water soluble fertilizer.
If your tomato seedlings get leggy, this means that they are not getting enough light. Either move your light source closer or increase the amount of light the tomato seedlings are getting. If your tomato seedlings turn purple, they need some fertilizer and you should apply the quarter strength fertilizer again. If your tomato seedlings suddenly fall over, they have damping off.
Growing tomatoes from seed is a fun way to add some unusual variety to your garden. Know that you know how to plant tomato seeds, a whole new world of tomatoes is open to you.