Growing potatoes in a greenhouse is virtually no different from growing the tuber out of doors. Potatoes require sufficient soil, a constant temperature of around 60 degrees Fahrenheit, and water about twice a week. Greenhouses are necessary for those who live in severely cold climates, because potatoes will not grow through frost. Keep the windows closed at all times, except for on particularly sunny days to allow for ventilation. You can grow potatoes either in pots or beds inside of a greenhouse to produce a large, starchy harvest perfect for homemade fries or mash.
Things You'll Need
- Potatoes for planting
- Pots or beds
- Fertilizer or compost
Place potatoes for planting in a window in the greenhouse that receives the most light. Their shoots need to start growing before you plant them. Allow them to sit in the warm, dry sunlight for at least 10 days prior to planting.
Set up your garden beds or pots. Depending on the layout of your greenhouse, you will either set up beds or pots for growing the potatoes. If using pots, make sure they are deep enough to support snaking potato roots. Mix compost into planting soil and fill your beds or planter. Lightly dampen before planting.
Stick the seeded potatoes into the soil with the sprouted shoot sticking up out of the soil. Fill any spaces around the shoot with more soil or compost to make it cozy. If using a planting pot, make sure it has adequate drainage holes, as potato roots easily mold. Place the pot near a sunny window, and aim at keeping the temperature around 60 degrees Fahrenheit. Potatoes will not grow if the temperature reaches or exceeds 80 degrees Fahrenheit.
Water the potatoes two to three times per week. You don't want to over-water, as again, mold will ruin your potato. The soil should be moist, but not saturated.
Move your potato pots outside. If you are planting the potatoes in pots during the winter inside the greenhouse, you can move the pots outside once spring arrives. Only do this if you are in a moderate climate that experiences warm (50 to 60 degrees Fahrenheit spring temperatures). Outside air allows for greater ventilation and prevention of mold. You can return the plots to the greenhouse at night if the temperature drops.
Stop watering once the potato plant leaves turn yellow and die. This does not mean your potato plant is dead; it means the spuds are maturing. Two to three weeks after the leaves die, the baby potatoes will be ready to be harvested. If you prefer bigger potatoes, you can wait an additional four to six weeks before harvesting.