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How to Create an Heirloom Tomato from an Heirloom Tomato:

Harvesting a Cherokee Purple Heirloom Tomato
Above: Harvesting a "Black Mom's" Heirloom Tomato.

Selecting and Harvesting Heirloom Tomato Seeds

Start with an heirloom. If you start with a hybrid you will get part of the genetics you want or nothing at all, so do it right and get some known to be heirloom tomatoes. Many hybrids will reproduce but many do not produce viable seeds. All you need is an heirloom tomato from a farmer's market, a friend, or your own, but be sure it's an heirloom and not a hybrid. If you don't know, assume it's a hybrid.

If possible, choose your tomato carefully. Select from a strong and healthy plant that has fruited abundantly. I like to use one of my earliest tomatoes, in hopes that I will select the genetics which will fruit earlier. Sacrifice one of your best tomatoes for seed.

Take your tomato and let it rot in a cool place for several weeks. Two weeks is enough while four weeks of rotting is preferred. The acid inside the tomato is preparing the seeds for successful storage during this rotting process. Let your tomatoes that you plan on taking seed from get good and rotten. Then take those tomatoes and squish and strain the juicy seeds over a tight meshed strainer. Pick all the bits of rotten tomato out of the seeds you strained out as good as you can and let them dry in a warm and dark place. Do not let them see light, for this can ruin your seeds. I usually let my seeds dry right on the strainer. Move them around so that they all get good airflow as they dry and let them dry for as long as reasonably possible. Months is ok. Then store them in paper envelopes or something porous. Plastic bags will work but won't preserve your seeds as well as paper will. They need air.

Planting and Timing

When it comes to planting seeds, timing matters. It takes 10-14 weeks to germinate and get your seedlings ready. Higher temperatures will make germination happen faster but don't go above 95 degrees f and as soon as seeds sprout, lose the heat. Planting just before or on a full moon is beneficial as the moon's gravity will make the seeds absorb water better. You can plant in the garden exactly after the last frost for your area. I use the moon in combination with the last frost and hopefully come up with the best day to wet seeds. If you go by these guidelines, your plants are prone to starting off healthy in all regards.

The Grow Room

Your grow room needs to be clean and tidy and able to be kept that way. You can't have stuff that can get wet lying around. You want reflective walls or to make them reflective, and enough room to move around in, but tightly packed so that you're using your lights efficiently. Flat white paint is the best reflective coating for your walls. The seedlings might need to be off the floor, so that you can get heat underneath them. You need power outlets. Otherwise, you can be creative and use what works for your situation. You need ventilation fan(s) and you need a fan for gently breezing the air around (not visibly moving any plants though.)


Tomatoes send out a tap root as their first prerogative. They need 3.5" deep pots to shoot out a good tap root. It's not the "standard" flower pot size. I prefer 9 oz. cheap plastic cups with holes drilled in them for plants I want a little bigger, and 2.5x2.5x3.5 inch square pots for plants I want a little smaller when it's time to plant outside. This has to do with the amount of area required for each plant to be able to spread some leaves. The square planters are nice because they're sleek and fit the trays perfectly, but if you let plants go too long in these they won't have enough room for their leaves. If you use the square deep pots, keep in mind that after about 9 weeks, they absolutely need to be spaced out or they're fighting to get enough light.

You need trays or something to catch the extra water that drains out the bottoms. If you're watering properly, not much will run out the bottom, but you still need something to catch what does. tomatoes don't like humid or soggy environments. It can cause disease for the plants later in life so keep things as dry as possible.

Fill the cups loosely with dirt by scooping the dirt into them and shake the excess off the top. Do not push it in or do any mangling of it whatsoever, just scoop and shake and it will be perfect. Label it as necessary and put your finger in the center of the pot, one knuckle deep. One knuckle deep is perfect. Drop three seeds in; one for the dirt, one for the bugs, and one for yourself. Then gently pull some dirt back over the hole you punched with your finger. Sprinkle some water on it. Don't soak it but don't ever let that seed dry out for a second once it gets wet. I like to water it twice when I plant - lightly. This way it gets evened out better without compacting the soil. You want air to get to your roots after germination. Roots need air more than anything. more than water. Just don't let them dry or your season is over.

Before the seeds pop up, it's a good idea to cover your planted pots with a sheet of plastic. This will hold the moisture in and force it to more evenly disperse throughout the soil.


Seeds in dirt don't need any light. The moment they pop up, however, you want very intense light. Seedlings need intense and direct light from their first moments, so have your lights set to be on when they germinate. 16 hours per day is ideal, 12 is the minimum you can give them. Some people like to give them more than 16 hours, but evidence and experience shows it helps none and may harm. Use a timer and it's best to set it as close as you can to surround the sunrise and sunset. Make sure your timer can handle the amount of wattage you intend to put through it with your light. Some are better than others.

Lighting is the key. It's the biggest reason people end up buying seedlings instead of growing from seed. You need bright lights. Trying to grow seeds without lights and/or a greenhouse is wasting your time. Even if you have success, your plants will be too spindly to produce anything so don't waste your time. Start with lights. It's most of what you need to do it right and you can't do it without them. You have options.

Above: LED Lights and a few hundred tomato starts .

LED Lights:

I have a few setups that I like to use. My favorite are the led lights. I use the 300 watt models and the 90 watt model both. They're hyper-efficient, they get warm enough but not too hot and they have special characteristics which make them just the perfect lights for tomato seedlings. Using more red results in plants with more tightly spaces nodes and leaves with a very purplish tinge. They really look beautiful when grown under the leds but after a day or two in the sun they just look normal. Well, not normal, the leds tend to grow stalkier and stouter stalks. They look robust and very nice. The opposite of spindly. If you use too much blue led, you'll get spindly, so I use mostly red. A 300 watt light can cover about 3.5'x5'. A 90 watt ufo led can cover about 3'x3'. Different from HID lighting, these leds have the same intensity whether it be 90 or 300 watts. The 300 is just bigger, it's not more any more intense. The intensity of the 1 watt leds is perfect for tomato seedlings. Make sure any led you plan on using uses the 1 watt bulbs and also make sure it uses the 660 nm bandwidth light spectrum. These tow factors are both critical to success. The weak bulbs don't offer enough intensity and the 640 nm bulbs are the wrong color, resulting in lack of efficiency. 660nm leds are costly but they also save you on electricity and cooling.

High Pressure Sodium Lights:

High pressure sodiums are fairly efficient and produce the standard results you'd expect from a professional grower. 1000 watts is a nice and intense like you need for seedlings, which actually require more light than a growing plant. Just make sure when using these to keep the heat well away from your plants so as not to dry them out. With the 1000 watt bulbs, 1000 watts can cover an area about 8'x8' and still deliver high intensity. These are a pain but they do the job. Watch out for electrical and fire dangers when you use these babies though.

Fluorescent Lights:

If you use enough fluorescent bulbs and keep the height as close as possible without overheating the plants, these will work. One thing though; if you use these you will want to start your hardening process as early as possible and really do everything possible to maximize the light the plants receive. If you use fluorescents, cover every inch of your grow canopy with them. Keep them just high enough not to overheat your plants. They will work but you need to use them to maximum efficiency for good results. This is the cheapest lighting setup you can use but also uses the most electricity per plant.

Temperatures Throughout the Tomato Plant Seedling Stages

Temperatures are a big deal to your plants. During the germination stage, it's good to stay above 70 degrees and preferably warmer. You want to mimic the fluke unusually warm week in early spring. The warmer you can keep your soil, the faster your seeds will germinate. Anywhere from about 5 or 6 days at 95 degrees to 15 days or so at 60-70 degrees. Don't go below 65 or above 95 degrees f. I use radiating space heaters underneath my germinating trays to keep them at about 85 degrees until they germinate.

Cold Process for Abundant Fruiting:

After germination, it's good to cool things down slightly but keep them good and warm. Let them relax in the comfortable warmth until they get their first set of "real" leaves. After they get their first set of what I call real leaves, start turning down the temperatures a little more, take your temperatures down to between 50 and 60 degrees and keep them within this range during night-times and close to that during light times too. This "cold process" is causing hormonal changes within the plant to make the plant think it is in a more northern climate. This causes the plant to fruit prolifically in attempts to reproduce itself. So if you want loads of tomatoes, give your plants the best cold process you can. Keep them cold for about two weeks. Then you can bring the temperatures back up to as warm as you can get without going over 95 degrees for the duration of the seedling stage.


If you can use distilled water, use it. Distilled water, since it has no nutrients, will attract nutrients into it and be easier for the plant to take up nutrients when using distilled water. Otherwise most tap waters will work if you prepare it. In general, any water you put on your plants you need to let sit in a container for about a week before you plant to use it. This way the chlorine will dissipate into the air. Chlorine burns roots and causes the plants to go into shock if you use fresh chlorinated water. So let it distill for about week into the open air. You should also to oxygenate your water. Using Whisper brand fish aquarium pumps is the best way. I use some 18 gallon storage totes that I glue gunned some aquarium tubing into and aquarium air diffusers glued to the bottom of the plastic storage tote to oxygenate the water as it distills. The other reason to let you water sit is to that it gets to room temperature. Your plants will love you if you give them water at their existing temperature and free from chlorine. In cases where I was unable to properly oxygenate my water, I've used just a dash of hydrogen peroxide in the water. A metric dash, not a big standard dash as this stuff can burn your roots like chlorine will. Use it at your own risk. I don't recommend it because it will also throw off your Ph and might require you adjusting it.

You don't need to fertilize until the last week or two. Let them grow on their own and if they need any fertilizer, give it to them very cautiously. For seedlings, use about 1/5 full strength of your regular general purpose fertilizer. Don't waste your time killing your plants with fertilizer. There are plenty of better ways to improve your gardening than this. If you're the type of person who likes to fertilize stuff to death, concentrate on getting more oxygen to your roots. Yes, oxygen. Plant roots require oxygen, not carbon dioxide, so take that urge to over fertilize and over oxygenate all you want, it will actually help.

Over-fertilizing and over-watering are the two biggest problems with plants in general. Keep it in mind always because if you screw it up just once, you're probably done for the season. Always err on the side of too little when using nutrients. It's advisable to check your water Ph to make sure it's at 7 or slightly acidic, down to 6.3 is ok. If you need to adjust your Ph, you can use eggshells boiled in water to reduce acidity, or coffee grounds to increase it. If you don't mind chemicals, you can buy Ph adjusters.


After germination, more than one seed will likely have sprouted. Remove all but one of them. Choose one which is most upright and has the thickest stem and disregard height. You can transplant them if you want to and multiply your plants. If any pots are empty, you can carefully move an extra from one pot to an empty pot.

Hardening Off

You need to get your plants used to the great outdoors before they get planted into the garden. To do this, use a lightly breezing fan in your room and breeze the plants when you get the chance. Touch the tops of the plants as you pass them and stroke and bend them over at every opportunity. For the real hardening though, you need to take them outside several times into the real world. They're not ready for the full hot sunshine yet so wait for cloudy days that aren't overly windy. Watch them closely as you do it and take them outside for an hour the first day, then increasing the amount of time they spend outside until planting time. Hardening is necessary in one way or another or else your plants will suffer greatly when you try to plant them.

Transplanting Seedling Outdoors

When you take the hardened seedlings outside and go to put them in your well prepared soil, it's ok to bury them a little. Tomatoes, unlike most garden plants, like to be planted a little deeper. Some people even lay them on their sides to plant them, claiming it makes them shoot more roots out of the sides of the stalks and makes them grow faster. In my experience, they like to mimic nature and grow upright and naturally vertical. Water them well when transplanting and get them staked before they have a chance to get growing out of control.

Above: Remove any debris that will prevent the soil from draining. Do not use grass clippings or mulch on tomatoes.

Above: Harvesting a German Johnson/Brandywine Red mix heirloom tomato.


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