Potatoes
Potatoes take up a lot of space to grow. They are not expensive to buy so why grow them? The answer is simple newly dug potatoes have a taste that you do not get from shop bought potatoes. They are easy to grow and also store well for many months in a cool frost free dark room. They form an essential part of a growing plan to have produce from your plot for most of the year. They are also free from all the chemicals applied to shop bought potatoes.
Potatoes belong to the same family as tomatoes which are part of the Deadly Nightshade family. Like tomatoes all parts of the plant is poisonous except for the part we eat i.e. tomato or potato.
Potatoes are grouped into first early, second early and main crop potatoes. The early potatoes are harvested sooner and planted earlier than main crop potatoes. They do not usually crop as heavily as main crop potatoes or keep as long. They do however mature more quickly than main crop potatoes and give you that wonderful taste of new potatoes a month or more earlier than main crop varieties.
Some varieties are more suitable for boiling, roasting, or jacket potatoes. Some are waxier and some more flowery when cooked, there is a wide variety of taste and is fun to try new varieties. The flavor and cooking abilities will most likely influence your choice of variety to grow.
Planting and harvesting times:
Potatoes take up a lot of space to grow. They are not expensive to buy so why grow them? The answer is simple newly dug potatoes have a taste that you do not get from shop bought potatoes. They are easy to grow and also store well for many months in a cool frost free dark room. They form an essential part of a growing plan to have produce from your plot for most of the year. They are also free from all the chemicals applied to shop bought potatoes.
Potatoes belong to the same family as tomatoes which are part of the Deadly Nightshade family. Like tomatoes all parts of the plant is poisonous except for the part we eat i.e. tomato or potato.
Potatoes are grouped into first early, second early and main crop potatoes. The early potatoes are harvested sooner and planted earlier than main crop potatoes. They do not usually crop as heavily as main crop potatoes or keep as long. They do however mature more quickly than main crop potatoes and give you that wonderful taste of new potatoes a month or more earlier than main crop varieties.
Some varieties are more suitable for boiling, roasting, or jacket potatoes. Some are waxier and some more flowery when cooked, there is a wide variety of taste and is fun to try new varieties. The flavor and cooking abilities will most likely influence your choice of variety to grow.
Planting and harvesting times:
- First earlies – planted around late March and take about 10 to 12 weeks to grow. Plant about 30 cm apart and rows about 60 cm apart.
- Second earlies –planted early to mid-April and take about 14 to 16 weeks to grow. Plant about 30 cm apart and rows about 60 cm apart.
- Maincrop – planted mid- to late April and take about 20 to 26 weeks to grow. Plant about 37 cm apart and rows about 75 cm apart
Potatoes are chitted before they are planted. Some feel that only earlies need to be chitted as it gives the potatoes a head start. Some feel that earlies and main crop should be chitted. Chitting is just sprouting your potatoes in a cool but light place. Often they are put into egg boxes. The chits appear where the eyes are on the seed potatoes (small indents on the surface of the potato). Always plant the seed potato with the chits facing upward. If you want larger potatoes limit the chits to about 3 per potato.
Potatoes like a slightly acid soil. Never lime your soil before growing potatoes. It will make the soil more alkaline and encourage scab.
It is also possible, but success is not guaranteed, to plant first earlies under cover in February harvesting at the end of May. It’s a gamble that I have in the past had success with, growing a short row of potatoes. I did it many years ago using sash windows to protect the crop and warm up the ground before planting. Initially protection against frost was easy by pulling earth over the potatoes when a frost was due. Later on the plants were too large to do this and during May it was much more difficult to protect against frost.
There are several ways to grow potatoes:
One method used in the USA sometimes is to grow the potatoes in bales of straw. Our climate is too damp for this as you will just attract slugs into the bale to eat your potatoes. So I do not recommend it.
You can also grow potatoes in buckets or old compost bags. Use a 30 litre buckets with drainage holes are the ideal size. You plant on top of about 10 cm of old potting compost enriched with a slow release general fertilizer like blood fish and bone. Put about three seed potatoes in the bucket and add some more compost. Some people then add a second layer of potatoes. As the plant grows you add more compost. Keep repeating this as the plant grows. Potatoes are hungry plants so feed regularly. You can also use this method to start an early variety about July time protecting it in the autumn against frost to have new potatoes at Christmas.
Under black polythene sheeting
Slits are planted in the polythene and potatoes are planted under it. There is no need to earth up. I have not tried this but I would imagine that slugs could be a problem with this method
The traditional growing method
The traditional growing method involves digging a shallow trench about 15 cm deep. Line the trench with well-rotted manure or compost. Sprinkle a general fertilizer in the trench and plant the seed potatoes with the chits facing upward (The shop sells potato fertilizer with an NPK of 10:10:10). Carefully fill the trench in. Once the shoots have broken the surface, be prepared to cover the plants against a frost for the duration of the frost. The foliage is not frost hardy. I use fleece, net curtains, environmesh. Use anything really to keep the frost off. I have used upturned clay pots before now.
When the plants are about 20 cm tall earth the plants up. I also scatter some fertilizer each time I earth up. Earthing up is just raking up the soil gently over the plants to form a mound around the plants with just the top leaves showing. You earth up to protect against frost. Also the potato tubers under the ground grow upward so you are providing more soil for the plant to grow in and produce more potatoes. Lastly if potatoes are exposed to light the potato turns green due to chlorophyll formation. Green potatoes are poisonous due to the presence of solanine.
You will need to earth up a couple of times before the crop is ready. When flowers begin to form after your second earthing up is when the potatoes are beginning to form. Make sure that you water and feed at this stage to aid formation of your potatoes, it really helps at this stage of development.
Early potatoes are usually harvested when the crop is in flower or they fade. Do not dig them all at once, dig as required. Leaving them in the ground will allow them to crop more heavily. The first potatoes that you dig will have a very small harvest, maybe only 400 to 600 gms. They are dug this early purely to experience that new potato taste. New potatoes do not keep once dug.
Main crop potatoes are dug when the foliage dies back. When you dig them on a dry day, leave them on the surface for a few hours to harden the skins off so that they keep better. Use any damaged potatoes as they will rot in storage. Store in a dry dark frost free place, in breathable sacks or a box, hessian sacks are good to use.
No-dig method
You can get good crops with the no-dig method and the potatoes are very clean when harvested. As normal with no-dig you have a mulch on the surface. Use a trowel to remove the compost and plant the potato. When it comes to earthing up you add more compost. I also feed and water my plants as you would for the traditional method, some people would use something like nettle tea etc. I use tomato fertilizer.
Harvesting is much easier as you do not dig the potatoes out. You gently pull the plant out, most potatoes are attached to the plant. You then rummage around in the compost to find the remaining potatoes.
Growing potatoes using no-dig is the one crop of very few crops in my opinion that does not fit well with the no-dig principles as you need a lot more mulching material to avoid disturbing the soil and covering the potatoes when earthing up. You do get good results however, I get just on average about 1.7 Kg per plant in a good year for main crop potatoes.
Some Pests and Diseases
Slugs.
These burrow into the potatoes. Potatoes left in the ground after they are ready for harvest may get extra slug damage.
Blackleg
This is a bacteria disease causing a stunted plant yellowing of leaves and black stems. Potatoes go rotten.
Remove the plant and burn it. Make sure you rotate your crops.
Some varieties like Charlotte are resistant to potato blackleg.
Potato scab
The potatoes are edible just scabby on the surface. Do not lime your soil as this encourages scab. Also dry conditions encourage scab, so watering your plants is beneficial regarding scab.
Blight.
There is early blight and late blight it affects potatoes and tomatoes. You get a rapid spreading of brown watery leaves and stems. This spreads to the potatoes, which then rot in storage. The potatoes are edible but will have brownish marks inside the potato. This is the fungal disease that caused the Irish potato famine.
At the first sign of this disease cut the tops off your potatoes and burn them. Leave the crops in the ground for three weeks before digging up to allow the fungal spores to die and not infect your potatoes in the ground. The disease is likely in warm humid/wet weather. It is only transferred to plants when the leaves are wet, so water your potatoes at the base. The disease will spread like wildfire across the allotments in days. Cutting the tops off early can prevent the disease reaching your potatoes.
If you get blight please inform the committee so that we can warn other plot holders to keep a look out to give us a chance to stop its spread.
Some potato varieties are more susceptible to blight e,g, pink fir apple and some more resistant to blight e.g. Sapro Mira
Things to Do in March
At the moment its too cold and wet to sow outdoors. You can start things off at home on your window sill etc or you can wait.
Sow
Outdoors: Leeks, parsnips, peas, cabbage family, spinach, onions, spring onions, broad beans.
Outdoors under cover Beetroot, carrots lettuce, oriental leaves, radish, rocket, salad leaves, turnips, cucumber (late in the month)
Indoors sow tomatoes, aubergine, sprouts, celeriac, pepper, cucumber, florence fennel, globe artichokes, sprouting broccoli, sweet potatoes, kohl rabi, celery, chillies.
Plant Asparagus, broad beans, cauliflower, Garlic, Jerusalam artichokes, onion sets, peas, potatoes, Rhubarb, Shallots, spinach
Chit your potatoes before planting