Grow Tomatoes from Seed by catman529
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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

Step 1: Get the seeds

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

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

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

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

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

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

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

tomatoes.jpg
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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kpeoples83 says: Apr 29, 2013. 11:55 AM
this an excellent instructable! my tomato plants are growing well as you have shown in the pics at each step
kpeoples83 says: Apr 29, 2013. 11:55 AM
this an excellent instructable! my tomato plants are growing well as you have shown in the pics at each step
primeline31 says: Mar 29, 2013. 4:43 PM
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.)
Don,t try this at home says: Sep 8, 2009. 6:22 PM
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.
askaboutrudy says: Sep 30, 2012. 8:45 PM
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.
askaboutrudy says: Sep 30, 2012. 8:43 PM
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. ;)))
davee52uk says: Mar 14, 2009. 12:57 PM
...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.
Cristiano Ronaldo says: Oct 20, 2011. 3:23 AM
I did not have to wait. I took them right dry for 30seconds and planted and it's as big the plant On step8.
catman529 (author) says: Mar 16, 2009. 5:46 PM
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.
katuah says: May 22, 2009. 11:45 AM
That could almost be another Instructable on its own....
catman529 (author) says: May 22, 2009. 2:06 PM
Yeah good idea...lol I might just go and do that one sometime.
xtremd says: Jul 28, 2009. 8:43 PM
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.
catman529 (author) says: Aug 1, 2009. 3:07 PM
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
xtremd says: Jul 28, 2009. 8:49 PM
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) says: Aug 1, 2009. 3:06 PM
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.
xtremd says: Aug 9, 2009. 6:46 PM
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...
hcold says: Mar 14, 2009. 6:27 PM
One assumes you also choose the biggest and best tasting ones for thing. You know, artificial selection and all that.
catman529 (author) says: Mar 16, 2009. 5:48 PM
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.
mantishunter says: Jan 11, 2010. 12:24 AM
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?
Cristiano Ronaldo says: Oct 20, 2011. 3:19 AM
Give it more.time. Or plant more
Ronyon says: Dec 8, 2010. 6:31 PM
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.
Cristiano Ronaldo says: Oct 20, 2011. 3:16 AM
Tomatoes do not vine.
Cristiano Ronaldo says: Oct 20, 2011. 3:11 AM
My tomatoes look the same as yours!
iminthebathroom says: Apr 12, 2010. 8:28 PM
Why not the paper ones?  Curious... leaching chemical nasties or...
catman529 (author) says: Mar 9, 2011. 9:38 AM
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.
VidDroog says: Aug 18, 2011. 7:29 PM
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...
abhishek727 says: Jul 17, 2010. 3:22 PM
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...
rosemary gillespie says: Aug 19, 2010. 12:41 AM
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 ..
Mojo_JoJo says: Apr 25, 2011. 3:35 AM
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?
shawn_allen says: Jul 12, 2011. 4:51 AM
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.
ManyuX95 says: May 17, 2010. 7:38 PM
Oh man, :) I love how they look so hairy xD
CraTyr says: Apr 17, 2010. 4:10 PM
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.
TheBlackSharpie says: Feb 18, 2010. 8:37 AM
I dont have any shop light but I do have some old lamps. I need to know if a compact flourescent light buld (CFL) would do.

Thanks,
lordzion says: Apr 11, 2010. 4:25 PM
Yes
Dr.Bill says: Dec 29, 2009. 5:09 PM
You Live The Tomatoe Electric !

I too am a tomatoe grower and have been for about 40 years.
I was forced into it when I was young. Boy am I glad.

I have grown tomatoes well into winter, indoors. (cherrys)
I make the best  Spaghetti Gravey, its to die for.
But you! You have all kinds of other recepies and for that I thank you.
Well Done.
Whales says: Sep 1, 2009. 5:58 PM
O_O Middle Tennessee? thats weird so do I, I start my tomatos in April or MAy... but they are usually from little plants, I tried seeds this year, and I did it in March(late i know) but my whole garden flopped this year, so next year I'm going with just pots.
blueyes48 says: Jul 2, 2009. 3:14 PM
Each year, we just throw our seeds ( from the tomatoes the ones we eat and the ones we order) into a semi-prepared, mostly neglected bed starting after the first frost. At the first hint of spring they starting sprouting, and the ones that survive are very hardy. We just transplant them into the garden. This year we have 250 plants! We just let them sprawl, and always have just tons of tomatoes to eat and process! It feeds our turtle visitors also, lol.
fearless1 says: Jun 19, 2009. 12:06 PM
I notice that you tie the plant with a figure 8 to the support stake. Using a wide soft cloth as you do helps prevent the stems from breaking at the supported area. Nice help for my tomatoes to come.
hickarus says: Jun 18, 2009. 6:10 AM
I have grown tomatoes for several years and one year tried the "upside-down" (now marketed as the "topsy-turvy") tomatoes along with the usual in-the-ground kind. I had to build a sturdy rack to hold them up there and they grew just fine. But I won't do them again and here's why: when the sun beat on the containers the root systems got really hot and I don't think they liked that. The stalks became much more cracked and the stress of the heat just made the plants look tired! Plus, they required much more water for the same reason. I used 5-gallon buckets and filled them up with compost and soil to within an inch of the top. Of all my plants ( I had about a dozen plants in all) four of them were hanging and only those four ultimately became victims of the dreaded tomato hornworm caterpillar. They ended up with very low yield, ravaged by the horn worm and dried out stalks in the end. I think part of the reason for this was that I couldn't get in there and be seen by the critters with the buckets hanging up so high above. If it has worked for you, I'd be interested in hearing what you did different. Otherwise, I'll just keep mine in old Mother Earth. She gives them the life they need. Alternately, buckets or containers on the ground work well. In the end, good planning and foresight will get you the best results. Good luck, gardeners!
LuminousObject says: May 22, 2009. 12:30 PM
Awesome. I'll have to try this so I can put more stuff in my greenhouse.
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