Potatoes are a particularly rewarding crop and such a staple ingredient in everyone’s diet which should make them the first crop choice for all VegGrowers, novice and experienced alike. You’ll find that certain varieties are more suitable for different types of cooking. Some are best for chipping, others are salad potatoes but however you prepare them, nothing beats the taste of your own homegrown potato. You don’t even need a garden to grow potatoes as they make ideal container crops.
Potatoes are categorised into three types - first earlies, second earlies and maincrops. First earlies produce ‘new’ potatoes from June/July while maincrops are harvested in the autumn and are suitable for storing over winter. Extra early potatoes can be obtained by planting first earlies from late February under fleece or by growing individually in pots under glass. If you have some space grow a selection of all three types and you’ll have a succession of crops from June to October. If you only have room for one crop or are planting in containers then choose one of the early varieties. Although the crop is smaller, they don’t take up as much space and should be untroubled by blight. Potatoes are half hardy so are susceptible to any late spring frosts and early autumn ones. Potatoes must be ‘earthed up’, by covering the stem bases with soil, to stop light getting to the potatoes. Light turns them green, which makes the potato poisonous.
Soil & Growing Position
Potatoes require a sunny site and in a new location to previous potato crops. Aim to leave it as long as possible before planting potatoes in a place where they have been grown in before because of any potato-specific soil pests that will be hanging around from the previous crop. Ideally more than 3-4 years should elapse before you plant potatoes again in the same spot. Although the optimum soil would be light, loamy and well-drained, potatoes will grow in practically any soil and are often grown in wasteland or new patches of ground which are intended to be turned into veg patches as they suppress weeds and improve the soil structure. Avoid planting in known frost pockets as the new foliage is susceptible to frost damage. Dig in autumn as usual and if the soil was not manured for a previous crop then add in compost or farmyard manure. Potatoes prefer a slightly acidic soil so do not add in any lime, as you might with other veg crops. Prior to planting, make sure any big clods of soil are broken up.
Sowing Seed Potatoes
Prior to planting, you will need to ‘chit’ your seed potatoes. This is done by standing up the potatoes with the ‘rose’ end upwards. This is the end that has the most eyes, which will develop into shoots (‘chits’). Use egg boxes to stand the potatoes up in or alternatively just use trays – it doesn’t matter if they’re touching. Store in a cool but frost free and well-lit place, but not in sunlight. Chitting takes up to 6 weeks, when the potatoes should have several strong half to one inch long shoots. Don’t break off the shoots.
First earlies are planted from early March in mild regions, end of March for most areas and early April in colder ones. Second earlies are planted from early April and maincrops up late April.
Plant in narrow trenches 5” deep and 12” apart for earlies, 15” apart for maincrop. The closer you plant them together, the smaller the potatoes produced. The rows should be 24” apart for earlies and 30” apart for maincrop. Sprinkle slug pellets between the potatoes and then replace the soil over the potatoes, drawing it up to form a ridge above the trench.
Growing On
If a frost is forecast and shoots are emerging then draw more soil over the top to protect them. Once the stems are 9”-12” high, you should start ‘earthing-up’. Using a hoe, carefully draw up the soil around the plants to approximately 6” high, covering about halfway up the stems and leaves. This only needs to be done once and is to keep the light from reaching the potatoes and turning them green.
Crops will need watering well in dry weather, particularly once the tubers have started to form. Use Growing Success Organic Potato Feed to increase yields.
Growing Potatoes in Containers
You can easily grow your own potatoes on the patio in potato planter bags or potato barrels. There are many advantages to growing your potatoes in containers as opposed to in the ground. As you use fresh compost each time, there is no risk of lingering soil diseases. There is also no digging required and when the potatoes are ready for harvesting they can either be easily lifted or potato barrels and some potato planter bags have a flap near the bottom where the potatoes can be easily removed without disturbing the remaining plants. Potato bags take around 5 seed potatoes each so why not try buying several planters and trying different varieties in each one? For this type of cultivation, you should choose early or salad potato varieties.
Simply line the bottom 6” of the container with potting compost and plant the seed potato just below this. As the new stems start to grow, add more compost to cover most of the foliage and continue to do this as the plant grows until the container is full. Make sure you water them regularly, particularly in dry weather.
Growing Potatoes under Polythene
You can also grow potatoes under black polythene which is advantageous in that the soil is kept warm and moist, weeds are suppressed and you do not have to earth-up as the polythene keeps out the light. Plant as usual, sprinkle slug pellets (otherwise they will eat the plant underneath the plastic) along the mounded ridge and then place black polythene over the row. Use a spade to press the edges of the polythene into the soil to hold it down. As the foliage develops, it pushes against the polythene. Cut slits in the plastic and then pull the stems through. Harvesting is also easier as the potatoes have grown nearer the surface so you don’t have to dig deeply to get them out. When harvesting, lift up the plastic in sections so you only need to harvest each plant individually.
Keep crops well watered in dry weather; the vital time is once the tubers start to form. A liquid feed of a balanced general fertiliser every fortnight can help increase yields.
Harvesting
First earlies should be ready in June/July and second earlies in July/August. For early varieties, once the flowers open or the buds drop, you should then check the size of the tubers by carefully removing some of the soil from the ridge. They are ready to harvest as new potatoes once they are the size of a hen’s egg. Use a fork to lift the potatoes, inserting it into the ridge and away from the stem and lifting the potatoes forward. Make sure you get all the potatoes out when harvesting, no matter how small, as leaving any in will only create disease in the soil.
Maincrops are ready from late August for potatoes for immediate. Potatoes intended for storage should be harvested in September up to early October once the foliage has turned brown and the stems have withered. Cut off and dispose of the foliage and leave the potatoes in the ground for 10 days. They can then be lifted, allowed to dry for a few hours, placed in boxes and stored in a cool, dark and frost-free place over the winter.
