Every year, I think the volunteer potatoes will never come up. Probably they all winter-killed. Maybe I did such a good job digging them that I didn't leave any. Maybe the mice got them all....
Probably this line of thinking reflects conventional "wisdom" that the "proper" time to plant potatoes is a month earlier than the potatoes think it is time to grow!
At any rate, today was the first day I noticed volunteer potatoes in last year's beds. So it's time to plant potatoes.
Instead of planting potatoes early, I "pre-sprout" them in the house. This year I remembered all the details (I think):
- Remove them from the net bags they come in, quickly, because the sprouts will grow through the bags and break off when the bags are moved.
- Place them in ventilated containers (I'm using heavy plastic flower bulb crates) so they won't rot.
- Line the containers with a layer of newspaper to prevent sprouts from growing through the containers.
- Label each variety that's sprouting.
- Keep in a warm, somewhat light area for several weeks before planting.
When planted, the sprouted potatoes come up and grow really fast since they have already broken their dormancy.
I plant potatoes into a thick mulch. This year, it's the area still mulched from last year's tomatoes and peppers. Since it wasn't tilled, but was heavily mulched last year, it should be great for potatoes this year: light and leavened by millions of worm and ant tunnel.
Planting potatoes is a "no-brainer". I set a marking line down the middle of the bed. A "planting board" about 60" by 10", cut from a scrap of Lexan, is centered under the marking line. Arrows on the board indicate plant locations for 12" zig-zag centers down the row; stars mark 24" centers. Potatoes get the 12" centers. At each mark, I dig a hole and put in a seed piece, sprouts facing up, and gently cover it with soil and then mulch.
Pre-sprouted potatoes are easy to cut for seed, because you can easily see the active eyes. I cut them so there are at least 2 active eyes per seed piece. Depending on the number of eyes and size of potato, I sometimes make the seed pieces smaller than recommended--because the sprouts are already so well grown, they don't need as much energy from the seed piece.
If they aren't pre-sprouted, I try to cut the seed pieces the night before and let the cut surfaces dry to prevent rot. But with ideal growing conditions and pre-sprouted seed pieces, rat isn't a big concern.
I usually try to save the volunteer potato plants and grow them out, either in the place they appear or transplanting them. These are varieties that are especially freeze and rot resistant (mostly fingerlings--Purple Peruvian is the star so far). Eventually I want to try planting potato beds in the fall or during winter thaws, to come up in the following spring. This will give me planting work that I can do during the "off" season.
I've found that potatoes for seed store well in the entryway--somewhere at cool room temperature, in the light. If they are partially enclosed they won't dry out too much. Storing seed potatoes as you would eating potatoes just encourages them to make long leggy sprouts that get broken off, and then they have to sprout again. Stored in a cool light place, they make stout, strong sprouts.