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Growing Heirloom Tomatoes from Seed

Growing Heirloom Tomatoes from Seed

Mary Smith |

Are YOU ready to get planting? 

Have you already started planting but need a little bit of help?
Mary's Heirloom Seeds is constantly adding to our Planting Tips page!

Amana's Orange Tomato

Growing Heirloom Tomatoes from Seed

There are two Types of Heirloom Tomatoes: Determinate and Indeterminate. 
Determinate tomatoes produce the fruit all at once. These are typically bush tomatoes, and make the best tomatoes for container gardening. Since all the tomatoes are ripe within a short period of time, these are great plant choices if you plan to can or have a short tomato growing season.
Inderterminate tomatoes grow on a vine.  If properly cared for, will produce all season until frost.
**From there you have characteristic-based types of tomatoes such as cherry, beefsteak, purple, green, etc**

ROMA tomatoes growing in our raised beds

Preferred Growing Conditions

Tomatoes love sun, and lots of it. Determinate or bush tomato plants work best for tomato container gardening. Soil should be rich in organic matter. Compost works best mixed in with the soil, and is a great organic fertilizer. 

Tomatoes tend to do well in soil that is a little acidic. Get a soil pH tester if you are unsure of your soil's pH level. One of the easiest way to acidify your soil is to add coffee grounds or brewed coffee.

Mulch will be important around tomato plants. Since tomato plants prefer full sun, the soil will dry out. Mulch will help retain moisture in the soil.

Starting Tomatoes from Seeds 
I recommend soaking your seeds in water for up to 24 hours.  This can increase the amount of seeds that germinate and how quickly they sprout.  Use organic potting soil OR Organic Coconut Coir if you are seed-starting indoors or in small containers to be transplanted outside.  Whether you direct sow or plant in containers, plant tomato seeds approx 1/4 inch below the soil.
TINY tomato seedling emerging from Coconut Coir Pellets

Seeds can germinate in as few as 3 days (when I soak) and as many as 14 days. 

How to Plant Tomatoes

Space out tomato plants 13 - 17 inches apart. Really just follow the planting instructions with the variety you choose. It will all depend on the variety of tomato you grow. You just want to make sure they will have enough room to grow and the roots not compete with each other. You can plant tomato seedlings after the last frost. Seeds can be started just before the last frost.
Tomatoes do well in raised beds. Rows should be 4-5 feet apart. But, don't forget that determinate tomato varieties grow well in containers, too!

Companion Plants for Tomatoes

Growing these companion plants around tomatoes will be helpful: Basil, chives,oregano, parsley, onions, carrots, asparagus, marigolds, celery, Nasturtiums and geraniums.
Borage can deter tomato hornworms and is a must in my garden! 

Some plants actually are bad to the health of tomato plants.

Avoid these plants around tomatoes: black walnut, corn, cabbage, potatoes, kale, and rosemary.

When to Use Organic Fertilizer
It's a good idea to use organic fertilizer in your garden, and avoid the chemicals around your food. Typically, tomatoes are fertilized every 3-4 weeks, with the first fertilization at planting. Tomatoes are considered "heavy feeders" but there is a delicate balance between too much nutrients and not enough.  For more detailed info, read Organic Plant Food-Feeding Your Plants

Maintaining Your Tomato Plants

Not sure what to do in the meantime? You will most likely need to stake your tomatoes. Again, depends on the variety. Bush tomatoes may need to be staked or caged for support. But, indeterminate tomatoes, or vine tomatoes, will definitely need support since they continue to grow all season. A trellis works nicely with vine tomatoes or a tomato cage.

Should you prune tomatoes? Depends on who you ask! Suckers, or side shoots, grow in the "v" of the stem and branch. You can pinch them off or leave them. Leaving the suckers on produces more tomatoes. But these will be smaller tomatoes. If you have a large tomato plant, like the indeterminate, you might want to prune the side shoots here and there. But don't go too prune-crazy, you want these plants to produce.

When to Harvest Tomatoes
Tomatoes usually take 60-80 days from transplant to harvest. Just pick them when they have turned their full color. You can pick them early and let them ripen in the windowsill.
But, the best tomato flavor is one that has ripened on the vine.


Tomato Pests and Diseases
Keep an eye out for tomato hornworms. They are the large, beautiful (ugly) green worms that blend nicely with the stems.  Plant borage to deter these worms.

Diatomaceous Earth is another great Organic solution to pest control. Sprinkle DE around the base of the plant as well as on the leaves.   Do not use DE on flowers or flowering plants.

Organic Neem Oil can be used against "muching insects" but should be applied in the evening or early morning (according to the instructions provided).


If you have additional questions about getting started or would like more info please feel free to ask.  As always, I am happy to help.

If you'd like to check out some of our gardening tips, check out our fb page.


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I’m in zone 4a so I started my tomatoes indoors 4-5 weeks ago, in a diy starter mix that was equal parts coco coir, vermiculite, and perlite. Everything germinated well and quickly, then stalled out. The best I got was some teeny tiny true leaves that haven’t grown any further. I tried up-potting into organic indoor potting/starting mix, in case they needed a better growing medium, and they’re still showing no signs of progress. Meanwhile, the marigolds I started at the same time are having the same results in the diy starting mix, but thriving in the coco coir pellet tray I bought to test out. Any thoughts on what might be going on and whether they can be saved at this point?


hello – i live in santa barbara, so we have a cooler coastal climate. what kind of heirloom tomatoes would you recommend?

ken y,

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