TPS Report πŸ₯”

Posted: March 19, 2024

Growing Potatoes from True Potato Seed

In the 2022 growing season, I grew potatoes with spuds from a local gardening centre. I think that an unusually hot early spring tricked some of these potatoes into flowering. This was surely part of what inspired me to buy a pack of genetically diverse true potato seeds for 2023.

Modern potatoes are grown from existing potatoes, [making them] genetic clones of their parent, it is essentially the same plant. Seed potatoes are just small potatoes, a stem fragment from the parent.

Potatoes from true seeds means that the plant's genes have the opportunity to rearrange, allowing for genetic diversity as well as a wide range of colours and tastes. My goal in growing potatoes from true seed is the novelty factor. Potatoes can have red or bluish-purple flesh β€” these deep colors are antioxidants (I think) β€” and imagine how cool it would be to eat dark red mashed potatoes.

Except under special circumstances, potatoes are self-incompatible. This means that a potato cannot pollinate itself and produce good seed. Counterintuitively, this is a good thing for genetic diversity, as it helps to eliminate inbreeding.

The Little Potato that Could

Seeing as potatoes are in the same plant family as tomatoes, in my Canadian climate it is recommended to start them early indoors.

Two tiny potato seedlings in a plastic grow tray
Last year's potato seedlings under grow lights

I am not great at hardening off plants. Logically, an indoor environment is much more stressful than outdoors. I did not harden off these potato seedlings for long enough before setting them out. So, all of my little potato attempts died. I dispersed the dirt from the potato seedling tray over the area I had for the true potato plants. Instead, I planted some scrawny supermarket potatoes there instead and called it a day.

A month and a half later I was weeding and I saw that among the potatoes grown from tubers, there was one small potato plant growing where I didn't remember burying a tuber. I assume this is from a seed planted in the growing tray that remained dormant long enough to not be killed by me. It had a purplish pigment at the root of the leaves, which was unlike the other tuber potatoes growing in the same area.

This small potato plant was off to a late start, and was surrounded by weeds for the first month of its life, but showed determination. This potato plant didn't get very big, but still made a few pink flowers. In the fall, I harvested four small tubers from this plant. I did not eat a single one, partially because they're pretty small, but mostly because I want to plant them in 2024 to see what this little plant can do. This means that I have no idea what the inside of this potato looks like. I've been storing them in a small wooden box all winter. They have begun to sprout, and I think all four survived the winter.

Photo of this potato plant growing in my garden
Note the dark colour at the leaf root

A Note on Terminology

Potato seed terminology is confusing. The tubers that typically are planted into the ground are called seed potatoes. True seeds β€” products of genetic recombination in potato flowers β€” are given the acronym True Potato Seeds (TPS).

Although I am proud of my Office Space reference, I cannot claim to be the first to make this joke. In my research, I found that the Canadian blog Maker's Dozen "got the memo" with the blog post TPS Report: True Potato Seed.