Grow sweet potatoes in the greenhouse
Written by: Lars Lund
The sweet potato is a bindweed and not a potato at all. It is the roots of the bindweed that thicken and grow to look like potatoes, which is probably what has given it the slightly erroneous name.
You can grow sweet potatoes in your greenhouse. They require a lot of heat, and the temperature in the ground must be at least 15 degrees before you start.
Sweet potatoes are rich in vitamins A, B, C, and E, and have a high content of healthy carotenoids. The B6 content is also large. The whole plant can be eaten, that is, tubers, flowers, and leaves. The leaves are used in the same way as spinach.
Sweet potatoes take 100-120 days to develop from the day you plant a cutting in the ground until you can harvest. If it gets too cold, they go in dormant.
You can buy ready-made cuttings or cuttings that have their own root system and are ready to transplant. It is recommended to transplant them in a bed, so if you have permanent beds in the greenhouse, those are very suitable. A large deep jar is fine too. Choose the warmest spot in the garden and cover with plastic.
The soil must be very porous so that the roots can form thickenings without obstacles. Like neutral soil.
There are several sorts. The best known in the northern regions is Beauregard. Thaiti has different decorative leaves if you want to use them for raw food.
If you take cuttings from a tuber yourself, you can put them in a pot, and here they should have between 25 and 30 degrees heat. As soon as they are up and running and the temperature outside is 15 degrees, you can transplant them. The distance should be 30-35 cm between the plants.
On humus-rich soil, you should be careful not to fertilize. At least if you want a lot of tubers. Too much fertilizer only gives many leaves.
Except when transplanting, you should only irrigate when the soil is dry. The plant does not like too much moisture. The plant does not tolerate low temperatures, and from the 1st of October, the air temperature and soil temperature are usually so low that it is necessary to harvest.
Om Lars Lund
Danish horticulturist and journalist
Lars Lund has for many years engaged in the garden and greenhouse. Lars has published many books about greenhouses, and he has participated in many Danish horticultural TV shows. He is a walking garden encyclopaedia, and he has answers for most basic cultivation questions – also the more ambitious ones.
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