The potato is a tuber, and a tuber is a fleshy, food-storing swelling at the tip of an underground stem, also called a stolon.
Originating from Central and South America, potatoes were and were brought back to Britain it is said by Sir Walter Raleigh around 1586.
Since then breeding programmes have produced hundreds of different varieties.
Some varieties have white, brown, purple or red skins, coupled with either white or golden flesh.
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They are classified as early, second early or maincrop potatoes which refers to when the crop is ready for harvesting.
- Early varieties are ready for lifting approximately ten weeks after they emerge from the soil.
- Second earlies take 16 to 17 weeks to mature after planting.
- Maincrops varieties are ready 18 to 20 weeks after planting.
Potatoes like plenty of sun, and adequate moisture throughout the growing season to swell the tubers.
Normally good soil preparation coupled with rainfall will suffice.
Failing that manual watering will be required to ensure the tubers get sufficient moisture.
Storing qualities; Early varieties do not store well and should be eaten soon after lifting.
Second earlies generally store quite well but it is maincrop varieties, that are deemed the best varieties for storing.
Cultivation;
Week 1-2; order seed potatoes if you have not already done so.
When ordering one can estimate the quantity needed by remembering that six potatoes weigh approximately 0.5 kg (1lb).
Planting distance is 300mm (1ft) apart for earlies, and 400mm (16") inches apart for maincrop, in rows 600mm (24") apart.
When the tubers arrive set them up, 'rose end' uppermost, in shallow boxes or trays, and put them in a light, airy, frost-proof place to 'chit'
Chitting is a means to encourage the seed potatoes to sprout before planting.
Sometimes it is difficult to determine the 'rose end'
This can sometimes be made easier by locating the point where the tubers was connected to the root system (stolon). If this is located this indicates that the 'rose end' is at the other end of the tuber.
The potatoes are ready to be planted out when the shoots are 20-25mm (¾"-1") long.
Take care they do not get the tubers chilled, or for that matter too warm, a temperature of 4°- 8°C(40°- 45°F) should suffice.
Note; Chitting potatoes is not essential, the practice is mainly a time saving technique to grow the crops quicker, i.e. it gets the plants off to an early start.
Week 4; Plant two or three potatoes in a 250mm pot to get an early catch crop.
Alternatively; Plant two or three chitted seed potatoes (tubers) in large bags, one tuber should be sufficient in smaller bags.
Cover the tuber/s with compost.
Water regularly and never let the compost dry out.
As leafy green shoots (haulms) grow taller, gradually unroll the bag and fill in around them with compost.
Continue with this process until the bag is full.
Continue watering regularly, adding a liquid feed once a week.
Note; Different potato varieties mature at different times, with early ones ready in mid to late June, and later ones will carry on developing into July and August.
If an early variety is being grown then they are usually ready for harvesting when they come into flower.
With second early or maincrop varieties wait until top growth starts dying back.
Week 5-11; Check over seed tubers that are already sprouting and dust/spray with insecticide if aphids are spotted.
In poor light the shoots may become drawn these should be rubbed off to encourage more to develop, or cut them back to a leaf joint near the tuber.
Any seed tuber showing disease symptoms should be removed and burnt promptly to prevent further spread.
Week 13; Prepare ground, if conditions are suitable, if this was not done at the back end of the previous season.
Week 15; If weather and ground conditions allow, plant out previously chitted early varieties.
Form drills 150mm (6”) deep in fertile, humus-rich ground, rose end up, 300mm (1ft) apart in rows 600mm (24") apart, cover with a layer of compost or soil, then add a general fertiliser.
Fill in drills so that rows are slightly mounded.
Week 17; Maincrop potatoes can be planted from now to until early May if weather and ground conditions allow.
Form drills 150mm (6”) deep in very fertile, humus-rich ground.
Set previously chitted tubers, rose end up, 400mm (14”) apart along the row, cover with a layer of compost or soil, then add a general fertiliser, rows should be 750mm (30") apart.
Fill in drills so that rows are slightly mounded.
Weeks 20-22; Earth up potatoes when the haulms (tops) are about 150mm (6") tall.
Pull the soil up to the height of the uppermost leaves it doesn't matter if the lower leaves are buried.
Weeks 23-27; Keep an eye open for signs of potato blight (Brown blotches on the leaves).
If any signs are found treat accordingly.
If the weather has been particularly dry maincrop varieties will benefit from a heavy watering every seven to 10 days,
Note; Give them a good drench so that the water soaks right down to the roots - frequent sprinklings will just wet the soil surface and potentially create the conditions suited for the formation of 'blight'
Week 28; Check early varieties by digging up a root, and if of a suitable size commence harvesting.
Note; As a rule of thumb early varieties are generally suitable for picking about ten to twelve weeks after they have emerged from the soil (fourteen to fifteen weeks from sowing)
Most early varieties do not store for long, so it is sometimes better to pick as required.
As a guide; 2nd early varieties mature approx 16-17 weeks after planting, and maincrop, approx 18-20 weeks from planting.
Week 28; Now is a suitable time to prepare fresh potatoes for your Xmas dinner.
Use specially prepared cold-stored tubers, as home-saved tubers can suffer from pests or remain dormant, the choice is yours!
Week 32; Plant up three tubers to a 250-300mm (10"-12”) pot/bucket containing potting compost.
Place well rotted manure or garden compost in the bottom third of the pot, for moisture retention.
Note; Do not plant the tubers directly on to the manure / garden compost.
Just cover the tubers with about 50mm (2”) of potting compost.
Plunge the pots out in a well lit or semi shaded spot, grow on, and check periodically to ensure they don't dry out.
As foliage develops, 'earth up' the potatoes with more compost until the container is full.
Keep well-watered and use a general-purpose liquid feed.
Week 38; Lift a root of maincrop potatoes to check on size and suitability for harvesting.
If you spot any sign of blight, remove all foliage and stems immediately to prevent it reaching the tubers.
Week 40; Once maincrop potatoes have stopped growing, cut back the haulms (top growth) if you have not done so already, and harvest the tubers for immediate use or storing.
Burn all foliage suspected of blight infection, and only store unblemished tubers.
Choose a fine day to lift your potato crop, as this will help to harden the skins.
Push the fork down for its entire depth to avoid spiking tubers.
Broad-tined forks are ideal for this job.
Leave the tubers on the surface of the ground for several hours to allow the skins to harden.
Discard all green (poisonous) and undersized tubers, and set aside damaged ones for immediate use.
Select a few healthy egg-sized tubers for possible use as "seed' next year before transferring the crop to paper or hessian sacks.
Store them in a dark, cool, and frost-free location.
Week 42; Prepare ground for next years potato crop by digging liberal helpings of well rotted farm yard manure or garden compost.
Leave the top of soil rough, winter weather will break it down to a suitable tilth.
Week 45; Potato tubers in containers for cropping at christmas, should be moved to a frost-free area.
