Can You Start Growing Potatoes in August?



Can You Start Growing Potatoes in August?

Marie Shallcross 

It is possible to buy special seed potatoes which you plant in summer. These seed potatoes are the same as the tubers that you would have bought in the garden centre but they’ve been kept in cold storage, at just the right temperature to keep them dormant. I’ve given a list below of varieties you’re likely to find in garden centres and online. They are usually sold as “late cropping seed potatoes”. There are fewer certified organic seed potatoes available for summer planting, but you can still grow them organically. 

Getting started with seed potatoes

If you garden in the warmer areas of the UK or have a sheltered plot, then unless the weather really goes against us, you’ll be fine to start growing potatoes in August or even early September. The more northerly or exposed your garden, the sooner you should start, so you may decide to wait until next summer. You do not need to chit your late potatoes before planting them. They will take about 12 weeks to mature ready for harvest. 

For the beginner, growing your Christmas potatoes in containers and raised beds is easier than growing in the ground because: 



  • It's easier to keep slugs at bay. 
  • The soil is likely to be better drained, so there will be far less chance of rotting, should we  have a wet autumn. This is particularly useful for those who garden in heavy clay soil. 
  • You can protect potatoes in containers if there’s a heavy frost by bringing them under cover into a greenhouse or frost-free porch.
  • In more exposed areas of the UK, you could grow the potatoes in your greenhouse.
Whether you’re a beginner or a seasoned gardener, if you’re limited on space in your vegetable patch, then being able to grow potatoes on the patio also has advantages. If you’re growing the potatoes in the ground, then cultivate as you would for a spring sown crop. Tips for growing follow on after the suggested varieties. 

Sowing potatoes for Christmas Dinner – varieties

These potatoes are early varieties, chosen for late cropping potatoes as they mature more quickly than main crop varieties. 

  • Duke of York - heritage variety; good all-rounder 
  • Maris Peer - can be used for roasting as well as boiling/salads 
  • Gemson - bred from Maris Peer but not so good for roasting 
  • Nicola - longer than some other types; good resistance to slugs and eel worm
  • Carlingford - high yielding variety; useful if you’re feeding the five thousand on Christmas Day! 
  • Charlotte - a popular variety for salads; good yields 

Growing potatoes in the ground 

It's difficult to be definitive as soil and aspect will vary, as will your preferred growing methods. I’ve presumed that you’ll be growing the potatoes in rows and that you’re practising crop rotation or other method to reduce soil borne disease such as blight. 

1. Dig a trench or drill about 6” deep. This allows you to cover the tuber with about 4” of soil. The soil should ideally have a pH5-6, so slightly acidic and be rich in humus. It should also be free draining, to reduce the likelihood of the potato tubers rotting in wet autumn soil.

2. Plant the tubers in the base of the drill, about 12” apart for earlies, 12-16” for second earlies and 15-18” for main crop varieties. 

3. Cover the seed potatoes by using a rake or hoe to draw the soil over them and form low ridges over the rows. Provided soil is moist you shouldn’t need to water at this stage.

Now there is a choice of methods, you could use.

Either: 

The first shoots should emerge from the ridges after 3–4 weeks, depending on which type of potato you’re growing. The rows should be ridged up again to cover the shoots.Earth up two to three times as the foliage reaches approximately 6-9 inches in height. This stops any potatoes that grow near to the surface from turning green and inedible.

Or use a less labour-intensive method: 

Cover the whole area where there are planted potatoes with black membrane. This is to prevent light getting to the tubers and acts in the same way as continually earthling up the ridges. 

Using membrane across the whole area also reduces weeds – and therefore weeding. The membrane is permeable to water. 

The first shoots should emerge after 2-3 weeks, depending on which type of potato you’re growing. You’ll need to watch out for these, as you’ll then have to cut holes for the top growth to come through the membrane or plastic. 

A downside of this method can be that slugs decide to live under the membrane, so it may not be practicable for your situation. 

Growing potatoes in containers 


Growing potatoes in containers

Whether you use specially bought potato sacks, a large pot or re-use a compost bag, the general technique is the same:

1. Use a container at least 12“/ 30 cm deep and about the same diameter. 

2. Ensure there are drainage holes. 

3. Put a 4”/10cm depth of potting compost or mixed garden soil and garden compost into the bottom. If the container is a lot deeper than 12” then make this a deeper layer. 

4. Place 1-3 tubers into a 12” potato sack; ensuring the shoots, or 'eyes' are facing upwards. 

5. Cover with 6”/15cm of soil/compost and water well. 

6. Put them in a warm position in your garden and keep them moist but not wet. 

7. As the foliage develops, cover with more soil/compost. Leave a gap between soil and container top so you can water the growing potatoes.


Growing potatoes in raised beds


Growing potatoes in raised beds
This is almost a half-way house as the soil should be free draining, but you won’t have the option of bringing the potatoes under cover. 

The membrane technique works well in a raised bed - it’s easier to protect from slug damage when the weather turns colder protect the top growth from light frosts with fleece overnight 

Problems 


Slugs, eel worm, blight are your worst enemies. The above varieties have resistance to some or all of these. Blight is often less of a problem with late cropping potatoes as they develop foliage later. If your area is at risk of late blight, then grow under cover. 

A wet autumn is another problem, for which free draining soil and growing under cover are the best remedies. 


Harvesting

New potatoes should flower about 12 weeks after planting. The foliage will turn yellow as it dies; frost damage will turn it brown. Cut off the foliage and compost it. If they’re safe from slugs, then you can keep the potato tubers in the container or raised bed until you need them. I’d recommend digging them up if grown in the ground. 

Remember new potatoes do not store as well as main crop, so keep them cool, dark and frost free. 

home grown potatoes 

Here’s to a successful (partly) home-grown Christmas dinner!

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