Grow your own potatoes – It’s easy, weather you are growing in pots or the open soil.
Get some potatoes… for best results buy good quality seed potatoes, chose a variety that you like and is disease and blight resistant. Waxy potatoes are good for salads and boiling. Floury (high dry matter) are good for roasting, chipping, and jackets. If you can’t get seed potatoes, any potato will do (seed potatoes are guaranteed virus free). What type do you want earlies, second earlies, maincrop. Earlies grow fast, develop tubers and then stop growing, so are dug up early as new potatoes (if left in the ground they’ll be eaten by slugs, tops will die off and it will become a weed patch). Second earlies can be dug up early or left to get bigger. Maincrop have a long growing season and are dug up when the skins have hardened. All potatoes can be dug up as new potatoes after 10-14 weeks before the skin hardens. There are 5 stages to potato growth.
You might have heard about chitting seed potatoes, this gains you time. You can start them growing early in your house in a light, frost free, cool place. This develop short strong shoots (chits), giving you a head start on the growing. (If they chit in the dark they grow long week shoots, that will break off when you plant them).
Plant them in large pots or open ground, but not too early. They are not hardy (the leaves will be killed by frost), so don’t plant until after your last frost. They are hungry plants, needing your best compost or muck, both for nutrients and for moisture. Potatoes are great for breaking up new ground, why not try no dig potatoes with a lasagne bed.
Lasagne potato bed
Basically start with cardboard to cover the ground blocking the light and killing the turf. Cover with layers of organic material, whatever you have available. Start with bigger bulky material at the bottom (straw, leaves, wool), getting to smaller/ finer material at the top (grass cuttings, compost, muck). Layering carbon rich materials (browns), with a layer of nitrogen rich materials (greens), as if you were making a well stacked compost heap. Then plant your potatoes in the top and let grow. You get a fabulous crop and at the end of it, you have a lovely new veg bed without having to dig the turf/ soil.
Earlies – 30cm (1ft) apart along the row with 40-50cm (16-20in) between the rows
Maincrop- 45cm (1.5ft) apart along the row with 60cm (2ft) between the rows.
It will be 2 weeks before they are showing above the ground and then another 4 weeks until the top canopy growth covers the ground. This is the crucial time for weeding, we call it earthing up. The purpose of this is not to give a high pointy ridge – NO -, but to hoe/ rake/ weed the bed. Being careful not to damage new emerging shoots or leave too little soil on the side of the ridges which the tubers will grow out of and get exposed to light (which turns them green).
Then just sit back and let them grow…….
If it is a dry hot season, give them extra water. There are 2 key points when watering is important, tuber initiation and tuber bulking…
At between 6 – 10 weeks, tubers form at stolon tips but are not yet enlarging. In most cultivars the end of this stage coincides with early flowering. If the plants lack water during this stage a pathogen develops in the soil that causes Potato Scab. The potatoes are still fine to eat, but look terrible, and may need peeling.
From flowering onward the tubers are bulking up, getting bigger and bigger with time and water. Not all varieties flower, so this is not a good indicator, usually around 10 weeks onward. This is the time to harvest new potatoes.
Plants turn yellow and lose leaves, photosynthesis decreases, tuber growth slows, and vines eventually die. Tuber dry matter content reaches a maximum and tuber skins set. When harvesting you may find the mother potato that you planted, this is not good to eat.
- Scab – chose resistant varieties, water at tuber initiation stage
- Blight – chose resistant varieties (Sarpo varieties, Carolous). Cut off affected leafy growth and wait 2 weeks before harvesting tubers, so as not to contaminate the tubers.
- Black leg – remove effected plants
Read my report on Potato History.
Read my report on Easy Organic potatoes for a changing climate