Here’s what you need to know to grow organic potatoes in the backyard vegetable garden.
- Sunlight: Full sun
- Planting Depth: 3-4 inches (7-10 cm)
- Soil Temperature when Planting – at least 45F (7C)
- Planting Date – approximately 3 weeks before last frost. They can be planted in cold ground but it takes 3 weeks for the leaves to emerge/unfurl and we don’t want them frosted.
- Soil – average soil fertility. Hopefully a ph between 5.0 and 6.5 Sometimes scab appears on soils with higher pH but if you increase fertility (lots of compost) you can decrease scab problems. Do not use fresh manure on potatoes or you will encourage scab (a brown scabby scale on the tubers)
- Spacing: Plant 12-inches apart (30cm)
- Water needs – moderate, do not allow the tuber to go bone dry (drought) during tuber formation (when you see the blossoms)
- Nutrition needs – this plant loves to be well fed so don’t spare the compost or organic fertilizer here
- Rotations – do not follow with tomato family crops.
The only thing you need to start a potato plant is a small bit of skin and an eye – I’ve done it from potato peelings. BUT this is NOT recommended if you want to get a decent harvest. Cut the seed potato into chunks about the size of a big golfball at the minimum size and “hopefully” each piece containing two eyes. One eye and a bigger chunk of potato is acceptable. (Remember the chunk of potato is feeding the emerging plant until it gets leaves so the bigger the chunk, the stronger your plant will be)
After cutting, leave the chunks in a well-ventilated spot for 24 hours (give or take – it’s not rocket science) for the cuts to dry out and form some protective barrier. I’ve planted immediately and waited and never found that much of a difference but the data all recommends waiting.
Traditionally, potatoes were planted in trenches about 4 inches deep and then “hilled” to keep pulling soil up around the growing shoots so the hill eventually became 12-15 inches tall. I’ve walked down many a potato row hoeing soil up around the growing necks of shoots to get those tubers well out of sunlight range. (Green skinned potatoes indicate soil has hit the tuber and these are both bitter and not to be eaten in any quantity as they can make you ill)
Eventually I got smart and laid the tubers on the ground, and kept covering them with straw mulch as they grew. The mulch did the same thing as the soil – kept them from the sunlight and produced even moisture (very critical by the way for good tuber development – avoid ups and down in soil moisture for good potato crops). And pulling the mulch away in the fall (or reaching down for some fresh young tubers early in the season) was a heck of a lot easier than doing all that digging.
Rubber tires. Some gardeners put a rubber tire on the ground -plant the tubers on the surface and cover with mulch, soil or whatever they happen to have that will hold moisture. When the leaves peak through, another tire is put on top and the process is repeated. You get “stacks” of potatoes that are harvested by pulling away the tires. This works well enough, I did it one year to try it but I preferred the mulch method.
Other systems – there are a ton of plastic bag, netting and other wonder-systems out there now for you to play with.
The deal with all of them is that as long as you keep your potatoes well fed and evenly damp, you’ll get a crop.
It’s really your own preference as I don’t think there’s a “miracle system” out there (although the marketers will try to tell you there is) 🙂
When the plant dies back, you dig the potatoes. Pretty simple really. Leave them sit on the ground until the soil dries on the tuber. Brush tubers to remove soil Do NOT wash them if you want to store them. Cure for two weeks at 55F and humid and then store at 40F (4C). Do not store potatoes with apples (ethylene gas given off by apples will sprout the potatoes).
Potato blight – it’s the same problem as has hit the tomato growing areas recently. If it hits, there’s nothing you can do. Check out the blight links under tomatoes.
Potato bug. Voracious little critters – they’ll eat a plant almost overnight. Pick the egg cases and crush them and adults by dumping them into a bucket of soapy water. Rotenone and most organic dusts work on the adults but do rotate the product you use to avoid creating resistance.
Do you need other organic vegetable gardening tips?