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When are potatoes ready for harvest??

8 CommentsTuesday, 3 July 2018  |  SimplySeed

There's nothing to beat the taste of fresh new potatoes, however it's one of those questions that every new grower asks - "When are my potatoes ready for harvest?”

Actually it's not that daft because you can't see them like you can with tomatoes and by harvesting early, you are beating all those high prices in the shops.

Within a typical growing season, we are able to grow 3 types of potatoes. These are first earlies, second earlies and maincrop. The first and second early varieties are known as ‘new potatoes’. They have a shorter growing season than maincrop and are generally smaller in size but taste better.

 

 

First Earlies

Weather conditions permitting, first early seed potatoes are planted between mid-March and mid-April and should be ready for harvesting after about 10-12 weeks. That should ensure a nice crop of fresh potatoes for early June and into July, just in time for summer salads. There will be no sizeable tubers until the plants have finished flowering, so it’s not worth even thinking of lifting them until then. Once the plants have finished flowering, try a test dig to see if they are of a useable size. Only harvest what you need for a couple of days at a time. Leave the rest to grow on for up to 2 weeks. They will not increase tuber quantity, but the tubers already there will increase in size. It’s amazing the difference a week can make. (The variety shown in the video and the photographs below is Arran Pilot.)

Second Earlies

Planting second early potatoes is a good way of extending the new potato crop for a few more weeks and possibly right up until the end of August. They are generally planted around late April and should be ready for harvesting about 10-12 weeks later. Again, and as for earlies, they will not be ready for harvesting until they have at least finished flowering. A test dig will reveal whether they are a good size and ready for lifting. It’s important to remember to water both earlies and second earlies during dry periods. The tubers will need water in order to expand but it’s always best to give them a good soaking once or twice a week rather than a light watering every day.

Maincrop Potatoes

Maincrop seed potatoes are best planted during April. They need a much longer growing period than first and second earlies and will need a little more care and attention during the growing season, especially with watering. Earthing up, feeding and checking for pests and diseases should also be a regular routine. They should be ready for harvesting in about 15-20 weeks, which will be around mid-September onwards. Leave the stems to die off completely before lifting. These are the varieties you will store throughout the winter months and so the skins need to be set first if they are going to last the winter.

Harvesting & Storage

First and second earlies can be left in the ground until required but it’s not recommended to leave them beyond 2-3 weeks after their due harvest date. If they are left in the ground too long they will lose that fresh new potato taste as the skins begin to harden and thicken. They are always best eaten within a day or two of lifting and will generally only keep in a cool, dry place for about 5-7 days. Despite many opinions and recommendations, all potatoes do not store well in a fridge or freezer and will lose their fresh taste. They will also taste dry and sometimes sweet. Fresh is always best. Carefully use a garden fork and not a spade to unearth your potatoes.

Maincrop potatoes will store for much longer periods due to their thicker skins and texture. They can be kept in dry hessian or paper sacks and stored in a cool, dry, frost-free shed for many months, which should see you through the winter. Ensure there are no damaged potatoes in your sacks because they will rot and affect all the other potatoes. They also need to be kept in the dark to prevent sprouting and greening. Never eat green potatoes as they will contain solanine, which is quite toxic.

Summary

There has always been some debate about whether the flowers of potato plants should be removed. In theory, by removing the flower, the plant will divert more of its energy into the growing potatoes. However, the difference is thought to be quite negligible so it really all comes down to personal choice and preference.

When the flowers appear on the shoots and stems of potato plants, it’s a sign that the potato tubers are maturing. It is however only an indication and so a test dig will reveal whether they have reached a size considered ready for harvesting. If they are still very small then simply leave them for another week or two, in which time they will grow very quickly. With maincrop potatoes, wait until the stems have died down completely before lifting. 

As a guide, harvest first and second earlies 10-12 weeks after planting. Remember you can leave them in the ground for further 2 weeks, rather than lift them all at the same time. Maincrop potatoes are usually ready in September but again you can wait until November to lift them or wait until just before the first frosts.

It’s best to eat first and second earlies within a day or two of harvesting, although they can be kept up to about 7 days in a cool, dry and dark place. Maincrop potatoes can be stored in hessian or paper sacks and placed in a cool, dry and dark shed. They can be used throughout the winter months but do check the bags for any damaged potatoes and be sure to remove them. Always discard any potatoes that show signs of greening. Rub out and remove any sprouts on maincrop potatoes, although they are not thought to affect quality.

 

What is your potato crop looking like? Let us know with a comment below....

 

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Article Updated 3 July 2018

 


John Brown
Wednesday, 10 July 2013  |  13:22

Looking good although some have failed to germinate just coming into flower


SimplySeed
Wednesday, 10 July 2013  |  14:18

Hi, you don't say when you planted, but we did a note on this on the Facebook Page. This is one of the years that would have benefited from a late planting. Earlier (or should we say normal) plantings would have just sat in the cold and then the tubers can rot off.

Leave a week or so then have a test dig. In this weather they will be growing fast.


Ludwina Bhattacharyya
Wednesday, 10 July 2013  |  14:09

Is it true that the potato flowers have to be cut to get a better crop?


SimplySeed
Wednesday, 10 July 2013  |  14:22

It can improve tuber formation, BUT only slightly. I am not sure it is worth the effort put in.


Ian O
Wednesday, 10 July 2013  |  14:38

My potatoes are chest high and flowering beautifully. If what's below ground is as good as what's above ground then I am looking forward to a bumper crop!!


Cathryn H
Wednesday, 10 July 2013  |  15:26

Just about to come into flower, our season here in the north is a good 2/3 weeks later and 600ft altitude plus late planting due to this years late season, but huge healthy plants; very hopeful. Keeping soil moist during our long dry spell.


SimplySeed
Wednesday, 10 July 2013  |  15:55

Yes, water is the key, potatoes do not like being put under stress due to lack of water. However it is best to give a good soaking once a week, rather than little and often.