Starting Your True Potato Seeds

My question is in the post heading. I have GTS colorful mix. I’m wondering if I should start all of them this year or can I spread it out a bit?

1 Like

They are viable for several years under good conditions, however I suggest starting a lot more than plants you want to end up with, so I wouldn’t hesitate to just plant all/most. Unless you just want like 5 plants, then you might consider planting 30-50 of the seeds.

I wrote something up that I should really send out, here it is:

Ideal Planting Date: Start seeds between March 18th and May 1 (they are slow as seedlings so the earlier the better). They need at least four weeks to grow before transplanting them outside. Plant 3-5 times as many seeds as you want seedlings for, and cover them slightly with soil (less than ¼ inch).

Planting Instructions: When choosing or making your starting soil, be sure to include native field soil in the mix, but as weed free as possible (forest soil). Potatoes need to build relationships with soil microbes to thrive from the first moment of germination, in fact the more microbes the better. Keep nitrogen levels low– seedlings will be less prone to disease (damping off symptoms) and legginess when they don’t have excess nitrogen, and lower fertility will encourage them to build mycorrhizal relationships early and have sturdier stems.

Germination is best under cool, damp and dark conditions. I put them on a shelf inside for the first seven days. Germination is best at 60-70 degrees, cooler than other nightshades. Germination may be slow– up to two weeks. After one week (or if you see any sign of germination) be sure to put them immediately in a bright spot with at least 8 hours of sunlight. As long as you have enough sunlight, grow lights aren’t needed. As they grow, give them plenty of outside time in the wind and sun to build strong seedlings with strong stems.

Be prepared for uneven and spotty germination, tiny seedlings, and slow growth. Unlike other crops, potatoes have not been selected to have strong seedling growth. That’s our job now.

This is what your seedlings may look like after a month, even if you planted multiple seeds per cell. Choose the biggest seedlings to up-pot or translant and compost the rest.


Thank you that’s great info. I was wondering if you get full potatoes the first year or if you get little tubers the first year then plant those the second year? I looked it up and that is what I found. I’m excited to plant my true potato seeds this year!


Very timely post. I started mine in potting mix, with no native soil, and put them on a heat mat. :grimacing:

Normally people get micro tubers. The first year I planted TPS (the video of Joseph in my field in the course) I got some very big yields, but it’s never happened again like that for me. And yes you should keep your favorite micro tubers, I’ll write another letter about that, since you will need to taste test in the small chance you encounter a plant with bitter tubers.

The year I planted TPS, I got microtubers from 34 plants and small, but full-size (for that plant…it hasn’t increased the following year) tubers from one. It’s safest to expect microtubers that you’ll want to cellar and replant. But assuming you get enough, you could still cook and taste one for selection – the little tubers seem to be representative in flavor of the full-size ones.


When the first year I group from true seed I got a mixture of medium sized potatoes to the small ones so I guess it’s just a question of conditions that they grow up in

1 Like

Germination this year has been good so far. This picture (today) is from a group that were seeded 03-17-24. Also overseeded quite a lot since we’ve been relatively unsuccessful with other TPS up til now. The GTS TPS is growing great for us so far. :crossed_fingers:

Didn’t do anything special to sprout them. Seeded this roll, put it in a tray in a window (it had other friends in the tray who appreciated light), and had it there until it sprouted 10 days later. Now it’s under lights with other potato friends. They get ambient room temp - the room is between 50-65F, occasionally up to 70F. When it’s not snowing and at least 40F, they get to go soak in the sunshine and feel the breeze on their hairy little stems for a few hours a day. :wind_face: :potato: :seedling: :sun_with_face:


Hi, mine were sown on my hotbed with my eggplants ands peppers on the 19th of march, and sprouted about 10 to 15 days later. Temperatue was about 25°C, so about 75°F. Good germination rate so far. I did not know they could need lower temperatures. They were coming from Cathy and the “Croation Seeds Store”


I have sown TPS from Croatian Seeds Store as well. Out of 9 varieties, four have germinated, but I have sown small number of seeds.
My impression is that they need more like 6-8 weeks before planting out, at least in my case. They are extremely tiny seedlings initially and they stay tiny for a very long time. Tomatoes are sprinters and giants compared to them.


I agree with you @WojciechG. These are mine after 18 days from sowing, on a hotbed (20-25degCelsius)


Lovely babies :smiley:
I guess I will sow some more this week, learning by doing :wink:

I’ve got Cathy’s mix only and they’re an estimated 6 weeks in and some as big as smaller toms of the same age. I’ve had a bad experience with Vreeken’s Sarpo surprise that hardly did grow. SO it really matters where you get your seeds from. I think they’re in the seed train.

Just potted up the biggest tps plants of mine. Before and after pics. These are “clancy outcrosses” and “mixed tetraploid, red” from Cultivariable seed.


Just potted up mine. In general, they grow half slower than tomatoes for me.


Potted mine a few days ago. They are very diverse in vigour. There are some rare crazily growing ones in Cathy’s TPS


I’m hosting a Potato Lover Zoom on June 26th, add to your calendar.

Bring your questions, photos, maybe even some potatoes…

And add your photos to the potato album!


Here are mine as of the 17th of May. I’ll ask hubs to send me a more current one to add to the potato album. :potato: :grin:

1 Like

I just wrote a potato letter to all the people who ordered TPS (109 people!). Here it is, any corrections/additions needed? Need your help because too many things going on…

Subject Growing Potatoes from True Seed– Transplanting and Hilling

Transplanting the Strongest Seedlings
If you haven’t already, you can choose to transplant into bigger pots, or plant them into your garden. For the last few years I’ve transplanted mine into the field when they are between 1 and 3 inches tall, and that usually takes 4-6 weeks. They are slow and tiny! Other people grow them to be bigger before transplanting, it’s totally up to you and your situation.

Example: Choose the strongest seedlings to transplant.

But no matter what, just don’t let them get root-bound, because that will trigger them to stop growing, and put their energy into making tiny tubers before the plant is ready.

1. Select the Best Seedlings:
Choose seedlings with thicker stems and dark green leaves. Red stemmed seedlings will be more likely to have colored flesh.
Use a scissors and cut the smaller, yellow, or leggy seedlings at the base, avoid damage to the roots of the plants you want to keep.
Discard any yellow, weak, or leggy seedlings.

2. Prepare the Planting Site:
Potatoes prefer fertile soil without high weed pressure. Add compost (if needed) before planting. You’ll want to mound dirt around stems just like for tuber plants, so make sure you have space for that. I grow in single rows so I can hill with a wheel hoe.

Ensure the site receives full sun for at least 6 hours a day.
Space the planting holes about 12 inches apart in rows 24-36 inches apart.

3. Transplanting Steps:
Water the seedlings thoroughly before transplanting to reduce transplant shock.
Gently remove the seedlings from their trays or pots, being careful not to damage the roots.
Bury the stems in the same way you would plant tomatoes or other nightshades, leaving exposed leaves on the soil surface. This is great for leggy seedlings.
Water the seedlings.

If you’ve already transplanted, hilling increases yield, helps protect tubers from sunlight, and reduces weed pressure.

When and How:
Hill your potato plants when they reach about 4-8 inches in height. If the area is weedy, this is a great time to hill and bury weeds at the same time.
Repeat the process every 2-3 weeks or as needed until the plants begin to flower.
Use a hoe or your hands to gently mound soil around the base of each plant.
Cover the lower few inches of the stems with soil, leaving the top leaves exposed.

Sharing Your Journey
Growing potatoes from seed is a challenge, so we encourage you to share your progress with our community so we can learn together. Photos of your plants, questions, insights on your growing conditions, and any unique methods you’re using are welcome in our community.

Happy Gardening!

You potato seed steward,


Looks good from what I can tell. You have a lot more experience than I do growing potatoes (this is my first year), so I don’t know enough to know what I don’t know. :sweat_smile:

But the information you just gave was super useful! I’ll tell hubs to plant our babies sooner than later to avoid the possibility of them feeling root bound in the rolls.