Heirloom tomatoes are some of the most interesting plants that I ever grew outside. With a wide range of bizarre shapes, colours and flavours, these are fantastic plants for the garden. But do they grow inside. I was determined to try them in my greenhouse, and here’s what I found out.
What are heirloom tomatoes (and why bother trying to grow them)?
Before I get to my actual experiment, let me explain what heirloom tomatoes are and why I’d want to try them. The definition of heirloom is a little shaky, but many people talk about heirloom seeds as seeds that used to be grown but are no longer carried by mainstream seed companies.
Originally tomatoes were developed by communities in the Andes, and spread around parts of what is now South America, Central America, and Mexico. Apparently Spanish conquistadors obtained seeds during early conquests in the Americas and brought them to Europe.
European people grew fruit and vegetables in gardens and kept the seeds from their plants to carry over to the next year. People would trade with their neighbours, and communities would each develop a few favourite varieties. Over time, these varieties began to look different from each other (and presumably the people of the Americas pre-contact had many tomato varieties to begin with). These varieties would have been selected in each community for the ability to grow in their conditions, and also for their colour, taste and production.
As large seed companies developed products for industrial agriculture, it became clear that some tomatoes were better than others for mass production. They began to breed tomatoes for this purpose and at the same time fewer people grew their own produce. As a result, only a few dozen varieties were commonly used and many of the old varieties were lost or almost lost.
Some people who care about keeping this old genetic material around began to collect these dwindling tomato varieties and keep them. They did (and continue) to try to find others who will grow them to keep the diverse (and it is stunningly diverse) plants available.
Many of these seeds (now termed heirloom) produce incredibly interesting fruit and many creative people love to cook with them.
For several years I collected varieties and planted them in my garden (which was mostly tomatoes). Because I loved the interesting varieties, I insisted that we try some in our greenhouse.
My experiments with Heirloom tomatoes indoors.
We tried a few rows of heirloom tomatoes in the greenhouse our first year. In the beginning, it was incredible. We got this diversity of tomato fruit that awestruck the folks who came to our farmers’ market stall.
Several months in, however, it became clear that keeping these tomatoes in the greenhouse would become a problem. The tomatoes produced poorly compared to the commercial varieties that are bred for greenhouse production. Our records at the time were embarrassingly poor, so I cannot quote exact numbers, but we estimated production (by weight) to be about half to a third of the commercial varieties that we grew. That meant, for us, that we would have to charge two to three times as much for these products as we did for other tomatoes to make any money with them.
Also, it turned out that the heirloom tomatoes that we grew were much more susceptible to a strain of leaf mould that plagued our greenhouse. Many of the plants limped along and we naively refrained from just pulling them out until they were so far gone that they basically were not producing.
I also understand that these old varieties (and field varieties in general) are less able to handle the strong nutrient mix that we use for tomatoes generally, so they probably found our nutrient regime somewhat stressful as well.
Would I grow them inside again?
The short answer is yes. Yes, if it were for a hobby. I would have to be convinced that there was a very good market for them that would pay two to three times the price before I tried them commercially again. Right now I don’t see it, but the future is long, so who knows?
It is also possible that they could be justified as a part of a marketing campaign where they were used to drum up interest, so that the cost could be put together with marketing and there would be less pressure to make money from the sale of the fruit itself.
But if you want a plant that will produce fruit which is a conversation piece, heirloom tomatoes are the way to go. It’s potentially a wow-your-friends kind of plant, and for that purpose alone may be a good addition to your indoor garden.