The usual time for planting the first early potatoes is perhaps mid March to April, with a first harvest around mid summer. One can, though, try to produce a small crop earlier in the year provided the shoots are protected from frost damage. Since installing the two large glasshouses against their south facing wall, we have exploited the protection they offer to plant early potatoes in large pots. Today we planted this year’s first batch.
I am always annoyed by the garden centres offering their seed potatoes so early in the year. They have been on sale for some weeks already and some have shoots that are straggly and not very good for planting now, let alone in a couple of months when they will be needed. There is certainly no need to offer anything but first earlies at this time of year. If one does buy potatoes early in the year, I have had good results with storing them in the refrigerator, which retards the growth of shoots. I have found that they still produce good shoots when brought into room temperature to chit. In fact, I have stored tubers quite satisfactorily from February until a late under cover sowing in August for end of year new potatoes.
I usually order most online and get them delivered at the right time of year, but a bag of first earlies can be planted now, at least here in the south, if they are grown under some protection. First earlies generally take 10 to 12 weeks to develop their tubers, although growth will naturally be a little slow at this time of year. Based on previous years, though, they should be ready by the end of April and through May, and the current mild weather will be to their advantage. According to my notes, we planted on the 6February last year, and generally try to plant the first week of February so that we can harvest for the Finnish spring celebration of Vappu – or Valpurgis night as it is known elsewhere.
Each year we plant 20 tubers, one per 15 litre pot, which, to my mind, is an ideal size for this early harvest. Last year we planted 10 each of Sharpe’s Express and Red Duke of York. This year it is just Sharpe’s Express. The tubers have been chitting for a couple of weeks, although a week or two longer might have been beneficial. Each pot was half filled with compost and one tuber placed about two inches from the bottom, with shoots uppermost.
I grow these early potatoes in a 50:50 mixture of homemade compost and an organic peat free multipurpose. For the latter I have had good results with both Vital Earth and New Horizon. To half fill the 20 pots requires about three wheelbarrow loads of compost. To each barrow is added a good bucket of horse manure and a handful of fish, blood, and bone. These provide sufficient feed to support the entire growth of the potato plants, so no liquid feeding is needed. The organic matter, in both the composts and the manure, help retain moisture in the pots.
The pots will be watered from time to time and checked to see when the shoots appear above the compost. At that point it is important to keep an eye on the weather as if they are frosted the shoots are most likely to suffer some damage and, although they will probably recover, the harvest will be delayed. If a hard frost is likely, the pots can simply be topped up with more compost to cover the shoots. In practice, though, I rarely need to do this and by the time the shoots emerge from the half filled pots, the glasshouses provide enough protection from what are usually less harsh frosts. Further north, though, I imagine that more protection might be needed. One could always cover the pots with fleece or newspaper to provide a little extra protection.
When the shoots are a good few inches above the top of the pots, the compost will be topped up. No further manure or other fertiliser will be added to that compost, though, as that incorporated today will be entirely sufficient.