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Picture of Grow Tomatoes from Seed
I have been a tomato grower since 2008 when I grew my first tomatoes from seed.

Growing tomatoes from seed takes time and care, but ultimately it is not hard and the results are well worth it.

You will need either a grow light setup (cheap shop lights) or a south-facing window that gets plenty of sun (if you live in the southern hemisphere, you will need a north-facing window).

Use this instructable as a guide to growing your own tomatoes from seed.

UPDATE: Check out my new Web site on growing tomatoes. Grow Your Tomatoes
 
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Step 1: Get the seeds

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First, you need to get your seeds from a good source. I prefer online seed stores that accept PayPal, but this is just my personal preference. You can find tomato seeds in the garden center at places like Wal-Mart and Lowes. I buy mine from Tomatobob.com, who sells only heirloom seeds.

Research the seed company you are buying from to make sure they are reputable and that you will get good seeds from them.

I'm an heirloom grower, but you can choose to grow either heirlooms, hybrids, or some of each.

Step 2: When to plant the seeds

Tomatoes are typically sown 6 to 8 weeks before the last anticipated frost. Some say to sow them later, more like 5 weeks before the last frost, but either will work. Keep in mind that the earlier you start, the larger the plants will be when you plant them out.

To find your average last frost date, go to http://cdo.ncdc.noaa.gov/cgi-bin/climatenormals/climatenormals.pl?directive=prod_select2&prodtype=CLIM2001&subrnum%20to%20Freeze/Frost%20Data%20from%20the%20U.S.%20Climate%20Normals

I live in Middle Tennessee and start my seeds in mid- to late-February.

Step 3: Start the seeds

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Use seed starting mix, such as Miracle Gro or Jiffy Mix, to start your seeds. Fill a bowl with some mix and knead in some water till the mix is saturated but not soggy.

I use egg cartons to start my seeds in. You can use either the clear plastic or Styrofoam cartons; do NOT use the paper ones. Fill the trays with seed mix and firm the mix down into the cells.

If you are growing multiple varieties, you will need a labeling system to keep track of what tray contains what variety. Use tape, plant tags, etc to mark the trays. Be creative - do whatever works best for you to keep track of the varieties.

Plant the seeds about 1/4 inch deep, 2 seeds per cell. I use a pencil with the tip broken off to make a 1/4" deep hole in the center of each cell, and I drop 2 seeds into each hole and firm the mix around the seeds to completely cover them.


Step 4: Germination

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Keep your trays moist and warm to speed germination. Loosely fit plastic wrap over the tops of the trays, to keep water in but still allow for air circulation. Light is not required to germinate seeds.

In anywhere from 3 to 15 days, you should start to see tiny seedlings emerge.

When your seedlings are up and the first 2 leaves (cotyledon leaves) start to open, you will need to put your seedlings under a light.

Use a cheap fluorescent shop light for your seedlings. I use 4' fixtures that take 2 bulbs each. You can use regular fluorescent tubes, or ones specially made for plants. I use GE "Plant & Aquarium" tubes in my fixtures.

It's very important to keep your seedlings within 4" of the lights, preferably closer. If you keep the light too far from the seedlings, they will get very "leggy" - tall and skinny - and might collapse.

Keep the seed starting mix moist but not soggy, and water whenever the surface becomes dry to the touch (but NOT completely dry).

Step 5: Care for the young seedlings

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Keep the seedlings watered - not overwatered, but don't let them get so dry they wilt, either.

Make sure they are kept within 4" of the grow light(s). You can adjust the chain that the light hangs from, or you can put the seedling trays on books or boxes to adjust their distance from the light.

Make sure your grow light setup is in a room where it won't get too hot (80+ deg F) or too cold (below 50 deg F).

You will want the seedlings to be easily accessible, because you will be watering them often (every couple days).

Monitor your seedlings and make sure they are growing well. The cotyledon leaves should grow up to 1 inch wide each, and should be a healthy green color.

Damping off can be a problem - this is a disease that causes young plants to collapse at the soil line and die. If any of your seedlings damp off, remove the infected plants and the mix they grew in to prevent spreading the disease to other plants.

Step 6: Potting up

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When your tomato seedlings are showing their first set of true leaves, it's time to put them in individual pots.

I use 16-ounce disposable plastic cups. These work well and are cheap.

Fill the cups with Miracle Gro Potting Mix or similar potting mix. I use Miracle Gro because it eliminates the need to apply fertilizer manually.

Use a pencil to make a hole in the center of the mix in each cup. The hole should be about 1 inch wide and 3-4 inches deep.

Choose the best seedlings to pot up, and discard the rest. If you pot up more than you can grow in your garden, just give away the extra plants when they are bigger.

Carefully loosen the seed starting mix around your chosen seedlings. Gently scoop out each seedling, being careful not to damage the roots or stem. Tap off excess mix from the roots so they will fit easily into the hole you made in the mix in the larger cups. Do this one at a time, and when a seedling has been uprooted, put it in the larger cup immediately.

Firm the potting mix around the roots and the stem of each seedling. Bury the stem all the way up to the cotyledon leaves - roots will grow from the stem and benefit the plant.

Label your cups with the variety name of each plant. I write on the side of the cup with a Sharpie.

Thoroughly water all the cups. Make sure you don't splash potting mix all over the seedlings when you water them.

When the seedlings are all potted up, put them under the grow light(s) and keep them within 4-5 inches of the lights.

Step 7: Planting out

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When the danger of frost has passed, it's time to get the plants out in the garden. Your garden should be tilled ahead of time, and adding compost is good. Soil pH should be from 6 to 7 (slightly acidic to neutral) for tomatoes.

Dig a trench about 1 foot long, with one end deeper than the other. Carefully remove the plant from its pot and loosen the root ball. Place the root ball in the deeper end of the trench, and lay the seedling on its side with the stem in the trough.

Remove all the leaves from the part of the stem that is in the trench, and leave the top few leaves on where they will be above the ground. Bury the roots and bare stem in the trench, leaving only the top few leaves sticking out. Don't worry about their being sideways - the plant will correct itself and grow upwards within a few days.

Trenching plants allows roots to develop along the entire buried portion of the stem. They say this increases yields - I haven't done any tests of my own but it makes sense. More roots allow for more nutrients to be absorbed.

Repeat the trenching process to all your plants, keeping them spaced at least 2 feet apart (if you plan on pruning) or 3-4 feet apart (if you won't be pruning).

When all the plants are trenched, water them thoroughly and add mulch if desired. Drive stakes or cages into the ground, making sure you don't puncture the buried stem.

Step 8: Care in the garden

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Your tomato growing spot should receive at least 6 hours of sun a day for good yields. I only get at most 5 hours a day, but my plants sill produce fairly well.

Keep the plants watered, but not overwatered. Don't let them dry out or inconsistently water them. Not enough water can cause fruit problems like Blossom End Rot, and overwatering can cause the fruit to crack.

To prune your plants, pinch off the suckers (shoots that come out from between each leaf and the main stem). You can let a few suckers grow for more fruit per plant, but as a general rule, the more fruit you allow, the smaller they will be. Last year I let one sucker grow on each plant for a total of 2 stems per plant. The rest of the suckers were pinched off as they grew.

If you prune your plants, tie the stems to a stake. If you don't prune them, you can let them sprawl on the ground or place tomato cages around the plants.

Step 9: Harvest

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You should start getting ripe fruit anywhere from 2 to 4 months after planting out in the garden. Different varieties have different DTM (days to maturity), so some will ripen 70 days after transplanting and some will ripen late, 100 days or more. Usually when you purchase seed, the description will tell you the DTM.

You can cut or twist the fruit off when it is fully colored. Some heirloom varieties ripen green or have green shoulders when ripe; Google the varieties you are growing to see what they look like when ripe.

From this point forward, it's mostly watering and picking fruit till the season ends.

Here are a couple useful links to help with any problems the tomatoes may have:

Diagnose tomato disorders/diseases

Tomato pests

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ChristineN21 month ago
RyanO72 months ago

Shear The Beard

RyanO72 months ago
Ronyon4 years ago
I also like the trenching.Our raised bed was filled with tomatoes plants, with vines growing willy-nilly, but not producing much on each vine.
Next season,I will bury those runners, cleaning up my grow space and hopefully boosting yield.
I am checking out your web site as well.
Tomatoes do not vine.

Hang a nylon web from the garden center next to the growing tomato plant. The Nylon webs are usually about 5' wide by 15' long.
As the plant grows, gently poke the tip in and out of the net weaving. Train the side branches out along the web. Remove suckers.

By training your tomato plant to grow on the web, the weight will be borne by the nylon.

Be sure the webbing is supported by a strong system. I use galvanized water pipes. Electrical conduit will also work.

My later father "salvaged" some steel reinforcing concrete rebar grids from a construction site. He rolled the grids into cylinders about 2 or 3 feet across then placed them around his tomato plants. As the plants grew, the side branches poked through the rebar grid and supported the plants.

Most home improvement centers have 4 x 8 foot steel rebar grids you can purchase. These are MUCH stronger and longer lasting than those thin wire cones for tomatoes that the same store's garden center has.

davee52uk6 years ago
...and when you have got some tomatoes, leave one or two to get over ripe. Then cut them open and scrape out the seeds onto some tissue paper. Leave to dry and you have seeds for the next year.
catman529 (author)  davee52uk6 years ago
Yes, I should have mentioned that. Thanks for bringing it up. They don't necessarily need to be overripe, just at least fully ripe, when you might normally eat them. The preferred way of saving seeds is to scoop the seeds and gel into a container, and add some water so it doesn't dry out. Put it in an out-of-the-way area where mold can grow and the seeds can ferment. This removes the gel which is a natural germination inhibitor. When there is a good layer of mold on the surface of the seed/juice mixture, scrape it off and strain the seeds, rinse them and let them dry completely before storing them in an airtight container.
That could almost be another Instructable on its own....
catman529 (author)  katuah6 years ago
Yeah good idea...lol I might just go and do that one sometime.
Please do. its my first year growing tomatoes in my back yard and i am still a rookie (green as my tomatoes) and i would love to know how to save seeds.

To save seeds, when I am eating a tomato, I simply put some onto a bit of paper napkin. Then I mark the date and where the tomato came from, type, size, etc. After the paper napkin has set aside for a day or two everything is dry. I then fold the napkin and stick it into a place where I save seeds such as a clean peanut butter jar.

Another good way to organize seeds is to buy small plastic zip bags from a hobby or craft store. They cost about one penny each.

I don't worry about allowing any mold to grow or wash the seeds, I just do as described above and have a nearly 100% germination rate.

One thing that is important is to save your seeds every year from the best looking, healthiest and best tasting tomatoes. That way over the years you will be getting seeds that are optimized for your garden soil and light conditions.

Caution: do NOT plant tomatoes in the same spot year after year. This is because you will encourage little creatures that feast on the roots called nematodes. Keep track of what is planted where and use a three or four year rotation.

Tip: when your seedlings are tall and the ground is warm plant them as deep into the ground as possible. Trim off any side branches allowing only a few leaves to stick above the ground on about 2 inches of stem. This will do two things:
1. the two inches of bare stem will allow air to circulate.
2. the stem that is deeply planted in the soil will sprout roots giving moisture and nutrients to the growing plant. Being so deep, the heat of the summer will not bother the plant at all. Plants that are shallow planted can easily dry out because tomatoes do not send down a tap root.

Some of my deeply planted tomatoes have grown to the top of the garage and onto the roof by the time frost hits. So I know deep planting works quite well.

Also. Does anybody know what is the ideal soil moisture level for tomatoes? i made a Arduino controlled watering system that monitors soil moisture levels and adds water to keep the soil at the same level day after day. Its based off of the Garduino instructable. I'm just worried that i might be over watering or under watering.
catman529 (author)  winterfresh6 years ago
They say tomatoes need the equivalent of at least 1 inch of rain per week...not sure how that would work out with your Arduino system. Of course you don't want it to overwater either.
Thanks, I am going to add a LCD to my Arduino and a potentiometer so I can adjust the water level on the fly. Trial and error... Not the best but...
catman529 (author)  winterfresh6 years ago
Before I make an instructable on seed saving, check out my web page because I already have detailed instructions available... http://www.growyourtomatoes.com/saveseed.html
I did not have to wait. I took them right dry for 30seconds and planted and it's as big the plant On step8.
hcold davee52uk6 years ago
One assumes you also choose the biggest and best tasting ones for thing. You know, artificial selection and all that.
catman529 (author)  hcold6 years ago
Yes, it's recommended to choose the best fruit from the best plant for seeds with good genes. No guarantee that the plants they produce will be as good as their parent, but at least they have the genes for it so you have better chances of better plants.
Why not the paper ones?  Curious... leaching chemical nasties or...

Paper egg containers will hold water when you water plants, and get pretty nasty after a while, while the styrofoam ones are non-porous. I poke holes in the bottom of the styrofoam ones so they drain better, then water about once a day, depending on how quickly your soil dries out. Seeds need a lot of water to start, so paper egg cartons end up soggy.

catman529 (author)  iminthebathroom4 years ago
This year I used one 30-egg paper carton, but to avoid soaking the paper when watering, I painted it with hot wax which soaked into the paper and cooled to make it waterproof. When paper egg cartons get soaked with water, the paper softens and roots can grow through the paper, which can cause damage (planting the whole paper cup in a new pot does not make it decompose fast enough for root growth). Also, water soaking through the paper gives it more than twice as much surface area to allow for evaporation, which means you'd have to water a heck of a lot more often. I don't think there is enough outgassing of the plastic to make it a concern; after all, your plants will only be potted for a few weeks before going into the ground.
To not waste containers and space while experimenting with a stack of old seed packets (1990's on), as well as expectations of meager sun and heat in the NW, I used the 24-egg Styrofoam carton, placed in the oven with a CFL in place of the oven light...and it made a useful amount of germination heat, keeping the temperature in the 80's. It is also handy to write the data on the while lid and borders (and as well the lid can add reflective light, +/- foil to the oven surfaces). Then a spoon can simply make the transplantation hole in the new soil and then scoop out the hatch-lings from the egg carton to then fit the spoon-made new hole. Nicely, all 24 spaces had germination: basil varieties, pepper varieties, Korean radish and twisty peppers, various tomatoes esp heirlooms.. Of course for bigger seeds, not so useful...still stick the mango in a cup of water..attractive for the kitchen window sill...
jamesrdell1 year ago
I just dropped some seeds on the ground and wa-la sprouts in a few days
kpeoples832 years ago
this an excellent instructable! my tomato plants are growing well as you have shown in the pics at each step
kpeoples832 years ago
this an excellent instructable! my tomato plants are growing well as you have shown in the pics at each step
primeline312 years ago
What about drainage? I make drain holes in these plastic cups with a soldering iron. Otherwise, the roots can rot if you accidentally water too much (which is very easy to do.)
Did you use grow lights and if you grow them inside do you need the lights on them the hole time there alive.I'm growing them inside droning winter.
Also, there's a hormone that plants have (and that we have artificially made in a lab) that stimulates root growth and production, so there's plenty of things to consider in the body chemistry and functions of plants and stuff like that.

Peace.
What's up my fellow Marine (Tufflehounde).

No, do not keep the light on all the time, you can, but it's best to give plants a night, and a day, just like us humans and other living things.

It has to do with hormones. We heal better when we sleep at night, and our hormones are better rugulated.

Plants have a bunch of different hormones like humans and animals do. At night plants are also in their repair and rebuild mode like we are when we sleep.

I can get all technical with which hormones do what for us and for plants, but I won't.

basically they will have a larger growth hormone stimuli, and they with breath in alot more CO2 when the plants are having their 'Night Time'. Oohrah? Kill? Or Heal I should say. ;)))
hi i was growing cherry tomato seeds, and once they germinated there were no true leaves, just seed leaves. No leaf bud either. How to make the plant grow again?
Give it more.time. Or plant more
My tomatoes look the same as yours!
abhishek7275 years ago
Can't we use the seeds from the tomato itself? Are there any disadvantages to this particular approach? It just feels a bit weird to me to go and buy the seeds when we already have the tomato. Maybe the hybrid varieties you guys are talking about are seedless but...
I was just thinking the same thing. I don't see why not. As a child I used to let lemon and grapefruit seeds germinate and they came right from the lemon. If you want a special type of tomatoe then you kneed to buy the seeds if you have not been able to get the vegetable or fruit that you want to plant. Also I think that "bought" seeds are treated with a substance that helps them grow roots faster ..
I don't know of any seed suppliers in my area so plan to use seeds from the actual fruit itself. I usually throw seeds of fruits I've eaten into a flower pot and some do germinate however they usually just die off once the seedling has used up the seed. any idea how I can get the seeds (any) to start growing into a full plant?
Many times, especially with plants that reproduce sexually (as most do), the seeds that are retrieved from the fruits are not as good as the seeds from a supplier. The seeds from the supplier are grown specifically for harvesting the seeds to produce fruit-bearing plants. Seeds from the fruit may have a different mix of parentage from the seeds used to grow the plant.
ManyuX955 years ago
Oh man, :) I love how they look so hairy xD
CraTyr5 years ago
Will this technique also work for peppers? I know they are totally different plants, but if it worked it would make a nice healthier seedling.
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