Growing Heirloom Tomatoes

Black Krim - Hssiao His Hung Shih Yellow - Mountain Princess Tomatoes in a basket

Black Krim, Hssiao His Hung Shih (Yellow Cherry) & Mountain Princess (Red) Tomatoes

I have a slight obsession with heirloom tomatoes. And by “slight”, I pretty much mean “almost out of control”.

There are hundreds and hundreds of wonderful, beautiful varieties to choose from. Their taste is far beyond anything that you could possibly buy at the store. They come in solids or stripes in all types of colors from red and orange, to yellow, green, white and, my favorite, the black or purple varieties.

You can grow big, juicy beefsteaks or sweet, snackable cherry tomatoes and any size in between. We usually get our first tomato around Father’s Day in June and I’m already counting down the roughly 8 weeks until then!

If you’d like to have your own supply of heirloom tomatoes, let’s talk about how to grow those beauties.


A Few Heirloom Tomato Seeds

Start With the Seeds:

First, you need seeds. I buy my heirloom tomatoes from Baker Creek Heirloom Seeds each year, but they certainly aren’t the only ones out there. (That’s not an affiliate link, I just like them a lot.)

One pack of seeds will grow a ton of tomato plants. However, if you’re like me and want lots of variety and to have fun experimenting with the many types available, you won’t be able to buy just one packet.

For the past two years, I forced myself to only plant the seeds I had on hand, since I’ve bought far too many over the years. I’m already scoping out some new-to-me varieties for next year though, since the freshness of tomato seeds ranges around 4 to 5 years and I’ll need to restock soon. (Hooray!)

Where we live, we have hot summers with high humidity, but long stretches without rain. We also have heavy red clay soil. One of the very best performers for our climate is consistently Black Krim. However, one year, we had tons of rain and it was cooler than usual. The winner for that year was T.C. Jones, a large, tasty yellow tomato, and our Black Krim didn’t do that well. Do a Google search or ask around your neighborhood to find out which heirlooms will do best in your climate.


Starting Heirloom Tomato Seeds

Seed Starting Mix & Containers

Next, you’ll need some seed starting mix and containers. Don’t use regular garden soil; you want a nice, light mixture that’s specially designed for the purpose of starting seeds. I like to use the little plastic six-packs with trays that you can buy at garden centers (or even places like Wal-Mart) for my tomatoes. Once you buy them, you can re-use them from year to year.

Plant tomato seeds indoors about six to eight weeks before the last frost date in your area. Our last frost date (here in zone 7 USA) is April 15. That means by the end of February or beginning of March, I can get started. Some years I’m a little later getting going and that’s okay too. To find out the frost date for your area, check out this cool little tool at Dave’s Garden HERE. Just type in your zip code and it will tell you what you need to know.

Evenly dampen the starting mix with water and fill your containers. Place a seed in each section, cover with a thin (about 1/4″) layer of soil and press lightly on the surface. You can also plant two seeds in the same section and just snip off the weaker looking one when they both come up. Sometimes I do this, sometimes I don’t. It depends a lot on the age of my seeds. Fresh seeds will have a higher germination rate, so you shouldn’t need a backup one.

Set the container in a warm place while waiting for them to sprout. I find that the top of my refrigerator gives the best results. Keep the soil evenly moist (but not soggy).

Once sprouts appear, in around five or six days, they should be moved to a sunny window or under a strong light. If they don’t get enough light, the plants will grow tall and leggy. Since we don’t have a window that’s sunny enough to prevent this, I rig up a spot for all of my seedlings under my basement fluorescent lights (like this) or under a shop light.


Transplant Tomato Seedlings to Larger Pots Once Their First Set of True Leaves Appear

Transplanting to Larger Pots

In the past, I would skip this step and think it wasn’t important. However, as you can see by the photo shown directly below, it makes a huge difference in your tomatoes overall health, vigor and size.

difference between tomato plants that are the same age but transplanted to different size containers

These seedlings were planted at the same time. The one on the left was transplanted to a larger pot after its true leaves appeared, while the ones on the right were not transplanted up.

Once your seedlings develop their first set of true leaves, which are not the same as those little cotyledons – or seed leaves – that they have at first, then they’re ready to be moved to individual pots.

Gently loosen each plant from its starting six-pack container and transplant it to the larger pot. You can use potting soil for this stage, but still no garden soil. Plant the tomato deeper in the new pot than it was growing in its first home. Unlike most veggies, you can cover the stem with dirt, since tomatoes can grow more roots from it.



Fish emulsion smells to high heaven, but it’s good stuff. Baby plants only need a half-strength solution every couple of weeks and once more right before moving permanently to the garden, to help reduce the chance of transplant stress.


Hardening Off

A week or so before you plan on moving your tomatoes to the garden, you should harden them off. This just means that you need to get them prepared for the change from their sheltered, highly controlled environment to outdoor conditions.

Find a spot outside that’s out of reach of any free-ranging chickens (they can do serious and heart-breaking damage to seedlings!) and let your tomatoes hang out there for a few hours. Each day thereafter, extend that time by a little bit more.


Add epsom salts egg shells compost and plant tone to planting hole

Moving to the Garden

After seven to ten days, your tomatoes should be able to be moved to the garden. Don’t just stick them in the ground though, without doing a little bit of prep work.

Every gardener has their own method, but this is how I like to prepare my tomato planting holes:

  1. Dig a fairly deep hole where you want to plant your tomato.
  2. Add 1 shovelful of compost. (We make our own, but you can also buy some.)
  3. Add 1 tablespoon Epsom Salts. (This provides the plants with magnesium & sulfur.)
  4. Add 1 scoop of Plant Tone or Tomato Tone. (A natural fertilizer – looks like THIS or THIS & probably at your local garden center.)
  5. Add a big pinch of dried, crushed egg shells. (For calcium, though it takes a LONG time to breakdown, and also cutworms dislike the sharp edges.)
  6. Stir all of that together with some of the dirt from the hole.
  7. Once the hole is prepared, pinch off the bottom set of leaves from your tomato plant. Since tomatoes can grow roots along the stem, we’re going to plant them pretty deep and won’t need those bottom leaves.


Pinch off bottom leaves and plant deeply

Set the plant down into the prepared hole and cover with soil. Press on the top of the soil around the plant firmly and water well.

I like to mulch my tomatoes with straw – but not hay, since it’s full of weed seeds. (I haven’t gotten my supply of straw in yet, or I’d have a photo of that here. Everything should be mulched by next week though and then I’ll update the post!)

Mulching keeps the soil from fluctuating too quickly between wet and dry. It keeps soil conditions a little more even for your tomatoes, which helps them get less stressed from bugs and such. It also helps suppress weeds and keeps dirt from splashing up on the tomato plant’s leaves. Heirloom tomatoes are more susceptible to diseases that are carried in the soil.

Don’t forget to add a plant label so you know which variety you planted! I just use a permanent marker and labels made by cutting empty plastic milk jugs into strips.

Mountain Princess Heirloom Tomato plant and marker


Let Them Grow

Now, just sit back and let your tomatoes grow. Walk through and check your plants frequently throughout the following weeks so you can catch signs of disease or pests early, before they become a bigger problem.

In the future, I’ll talk more about pest prevention and homemade garden sprays, as well as harvesting and using your tomatoes, but that’s all for another day!


Seed Starting & Planting Tips for Heirloom Tomatoes

Did you enjoy this article on growing heirloom tomatoes? If so, let’s keep in touch! Be sure to sign up for my newsletter (HERE) and get my latest soap ideas, herbal projects, gardening posts and DIY body care recipes sent straight to your inbox, once a month(ish). No spam ever and you can unsubscribe at any time.

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Jan Berry is a writer, herbalist, soapmaker, and bestselling author of The Big Book of Homemade Products, Simple & Natural Soapmaking, and Easy Homemade Melt & Pour Soaps. She lives in the Blue Ridge Mountains with her family and a menagerie of animals, where she enjoys brainstorming creative things to make with the flowers and weeds that grow around her.

  • JessicaT says:

    Excellent article, thank you! I have not started tomatoes from seed in many years. I need to get my hands on some seeds; I would love to try different varieties.

    • Jan says:

      Hi JessicaT, I’m happy that you liked the article & hope you get some more tomato seeds soon too! (If you find a great variety that you like – I’d love to know about it. I’m always on the lookout for new ones to try!)

  • Lazy Harp Seal says:

    What is the coldest temp. you set out your tomatoes in? I have some Siberian reds who are getting ancy to get outside, and I could give them some protection, but it’s still a solid 3+ weeks until my last frost date.

    • Jan says:

      Hi! We usually put a few in the ground a week or two early and use Wall O’ Waters to protect them. I was going to mention that in the post, but it was getting so long I was afraid I was going to start boring people! :) So, thought I could write up about them another time. I don’t think I’ve done three weeks ahead of time, but definitely 2. We have pretty mild springs though, so it’s not like we try to plant tomatoes when snow’s on the ground or anything, but the nights do dip into frost territory. We got our Wall O’ Waters from a local little farm store, but you can also find them on Amazon. Really great little inventions – you just fill each section with water and they wrap around the plant and keep it protected.

  • Felicia says:

    Very excited to have planted 3 varieties of Heirloom’s this year! I planted Cherokee Purple, Red Brandywine, and Rutgers (for canning – highly acidic so do not require extra citric acid). Wanted to share a great up-cycle tip! I purchased the REFILL Jiffy pods for starting seeds and used the container that my birthday cake came in turned upside down to create a mini-greenhouse for starting seeds. The refills of the Jiffy Seed starting pods are much less expensive than buying the trays and my cake container actually stays closed better than the trays that you can purchase with the seed starting pods anyway! I have also used egg cartons, 13×9 baking pans with plastic wrap and anything else I could find that would hold water and warmth but the Cake container is the best idea I have done yet! Happy Growing Everyone!

    • Lazy Harp Seal says:

      Are you talking about the pellets that expand in water? That’s what I used this year, and I have mixed feelings about them. First, at my Home Depot/hardware stores they are about 10 cents each when they come in the 72p greenhouse (which includes the tray and dome) or 36 refill box. They are 16-20 cents each in bulk at other hardware stores, and for some reason, the ones that come in bulk are more tricky to get the netting off. The other brand NK pellets have a courser texture and dry out way faster.
      I kind of like them, I have good germination with them…but keeping them at the right moisture level is tricky, and they do get a white fuzz on the surface after a while. At 10 cents each, they aren’t braking the bank, but in the future, I’ll save them for the more “precious” seeds (tomatoes, basil, etc.) and choose something else for leeks, onions, chard, cabbages, etc.

    • Jan says:

      Hi Felicia, Thank you for sharing your wonderful seed starting tips with us! I haven’t tried growing Red Brandywine or Rutgers yet (two more to add to my wish list – hooray!) :)

  • lotta joy says:

    I didn’t get my tomatoes planted this year and I’m going to be kicking myself in a few months. Now I wonder why I always planted my tomato plants “laying down”, and bending the stalk where the “main stems” grew instead of just making the hole deeper! I guess I saw my grandma doing it that way and never gave it a thought. She also added a tablespoon of sugar and planted them next to Marigolds.

    • Jan says:

      Hi Lotta Joy, I’ve planted tomatoes horizontally as well. When we first started gardening here, the soil was such heavy red clay, it was hard to dig down but so far, so that method served us well. I thought about mentioning that, but I was already writing a mini book so thought I should stop somewhere. :) I love your grandma’s tradition of adding a tablespoon of sugar; I’ll have to look that one up – I bet it has some type of good effect! :)

  • lottajoy says:

    I have no idea why she added the sugar, and maybe she didn’t either, but she mixed it in with the Epsom salt to keep ants from invading the sugar.

    • Jan says:

      That is so interesting! I have more tomatoes to plant tomorrow – I’m going throw some sugar in a few of the holes and see what happens over the season!

  • lotta joy says:

    Don’t take the chance on having carnage due to something my grandma did. According to her, they made the tomatoes sweeter, but she also left her groceries in the trunk of her car once…..until the smell convinced her there was a dead body inside. lol (there’s more but….) She planted her tomatoes side by side with marigolds and many years later I found out that it DOES serve to keep a lot of bug problems away from the tomato plants. So there’s that in her favor.

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