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Old December 18, 2009   #2
Tom Wagner
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Join Date: Aug 2006
Location: 8407 18th Ave West 7-203 Everett, Washington 98204
Posts: 1,157

Tom K,

You have been after me to post something on this for a while, therefore, I may as well jot down a few simple rules, suggestions, or tips.

Sow seed 6 to 8 weeks before planting outdoors in the Spring.

Temperatures for germination is best around 72-78 F. but don't go over 80. Once the seedlings are up cooler temperatures for growing out are preferred. I even like to give the seedlings some direct sunlight outdoors if you have a protected area out of the wind for a hour or two at at least 55 or more in F.

Depth of sowing is rather important. Just barely covered is OK. I usually sow in 72 cell trays. I fill the tray, level it off, gently press my fingers in the soil media to make a shallow depression and cover with more soil media. I like a sterile peat, vermiculite, perlite to cover with over a customized mix of the same with some worm castings, dolomite lime, etc. mixed in. I am organic 100% for the last number of years.

The 72 cell trays allows the soil media to dry out quicker than in a solid bed of soil. I try to keep the media watered but a bit of drying out between waterings keeps the damping off to a minimum. Potato seedlings appear very spindly when young and that is where a bit of direct sunlight will harden off the tenderness.

I like to sow several seeds in each cube, since potato TPS does not all germinate at once. I may sow from 3 to 10 seed to maximize the competition pressure as I want rather tall seedlings to develop as to transplant these about 3 to 5 weeks later burying the cotyledons and a true leaf or two in the first transplanting in the greenhouse. I transplant again into the 72 cell trays as to force the seedlings to grow tall so that I can bury more leaves when I talke them to the field. The seedlings may be very brittle, all the more so than tomato seedlings, so be careful!

When I go the the field after all danger of frost is gone, I make a trench in the ground within a hilled up row of soil. As the plants grow I have loose soil to cover the growing plants several times during the next few weeks to months.

The plants will be a bit later than potatoes grown from tubers especially if you planted those in early April and the seedlings in May sometime. I try to grow the seedlings to the point where they mimic regular potato plants and match the potential yields of that clone.

Spacing is about 10 inches apart in 3 foot rows. I augment the soil with organic feritilizers such as worm castings, dolomite lime, rock phosphate, alfalfa meal, bone meal, green sand, cottonseed meal, blood meal, kelp meal, humic shales, compost, etc.

Harvesting occurs when the plants start to die down. I make individual selections and bag the hill separate if it is good, otherwise I take one tuber per non-selected hill to plant for the next year. Sometimes the seedling year does not allow for the full expression of the clone to shine and the second year will determinine if you have a winning clone or not.

Potato storage is a long subject. I try to allow the tubers to air dry on the surface of the soil before I pick them up. Good ventilation is important for the next few weeks and then some kind of cool or cold storage for the winter. I rely on a cool garage out of direct light much of the time.

Tom Wagner
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