By Privatepike
United Kingdom 
i planted homeguard seed potatoes in march in organic compost from a garden centre into brand new growsacks and placed them in a unheated greenhouse, they grew nicely until they reached the top of the bag, then the leaves started to go black, i thought it might to hot so i moved them outside, fleecing them overnight, they picked up really well,then in april they went black again, and are still dying. why is this.
14 Apr, 2012
Were the sacks which you bought already full of compost or did you buy the empty potato sacks that you fill yourself? You should have placed about 4" of compost in the bottom of the sacks and than placed 3 or 4 tubers in each sack and covered them with about 6"inches of compost and as they sprouted, continued to cover them with compost and fertiliser until the sprouts reached almost to the top of the sack. There shouldn't have been enough sprouts sticking up from the compost to become burnt off by the frost or cold this early in the season. Did you plant they tubers too near the top of the gowing bags?
14 Apr, 2012