It can be confusing knowing when to harvest potatoes
Knowing when to harvest potatoes is based on whether they’re an early potato or main crop and what happens to their foliage and flowers
One of the easiest edibles to start off with as a beginner gardener is the humble potato. They’re relatively low-maintenance, can help cultivate the soil, and will also suppress any weeds that try to compete with them. They’re also very fun to dig up and eat! But when are potatoes ready to harvest? This is probably the most taken for granted kitchen gardening knowledge you’ll find. Seasoned gardeners will ‘just know’ when the plant is ready. When you’re just starting out it’s a bit of a head-scratcher.
The answer lies in which type you’ve planted. The vast majority available will fit into the categories of ‘First Early’, ‘Second Early’, and ‘Main crop’. Read on to know what to look for when it’s time to harvest potatoes.
In my opinion, the best type of potato to grow is one that fits into the ‘First Early’ category. These include the Red Duke of York, Lady Christl, Arran Pilot, and scores more. This year I’ve grown Pentland Javelin which is a type that matures slightly later than other First Earlies.
‘First Earlies’ are one of the earliest garden crops to mature. You plant them from St Patricks Day to mid-March and then dig them up around 10-12 weeks later. Typically in June to July but sometimes earlier. They’re easy to grow, don’t tend to suffer Blight, taste tender and delicious, and fun to dig up in early summer.
The way you know that first earlies are ready are by their flowers. Early potatoes generally produce flower buds that sometimes bloom and sometimes don’t. It’s time to dig up your tender, homegrown potatoes when the buds drop or the flowers that do bloom begin to fade. Another good indication is seeing unopened flower buds dropping from the plant. At this point the leaves will still be green but some will begin fading to yellow. The potatoes from earlies will be about the size of an egg with skins so tender that they’ll melt in your mouth.
If you leave first earlies in the ground, they’ll continue to grow. That means that if you’re not quite sure if they’re ready to harvest, just leave them in a little while longer. The potatoes will grow larger though.
Potatoes that fall into the ‘Second Early’ category include Nicola, Maris Peer, Jazzy, and Kestrel. They differ only in one way from first earlies — they mature about three weeks later.
As for planting times, you can get them in the ground at the same time as first earlies but it’s better to wait. The traditional day to plant them in most of the UK (zone 7-8) is the first day of spring, in late March. Just think about it, if you plant them at least two weeks after your first earlies then the harvests are staggered by five weeks. That gives you time to eat your first crop before another massive harvest is ready.
Use the same indications for harvest as first earlies and look for blossom drop. By the way, how gorgeous are potato flowers? They come in all different colors and potatoes were actually grown in Europe as ornamentals before they were grown as food crops.
If you’re looking for recipe ideas for larger second earlies, try Hasselback potatoes. With their tender skin you don’t even have to peel them.
Main crop Potatoes
Think of a massive baking potato and it’s most likely a main crop. Varieties in the UK include Cara, King Edward, Pink Fir Apple, and Purple Majesty. In the USA, they’ll be Russet varieties.
Main crop potatoes are planted at the same time or up to a month later as second early potatoes. They need a lot more time in the ground though at about 20 weeks. Over the summer they swell and grow resulting in harvests large in both size and quantity.
You harvest main crops in late summer, typically in August to September. You know the time is right when much of the foliage on all your plants begins to turn yellow. It will then shrivel up and turn brown and dry, and eventually only shriveled leaves and stems will be left. At any time during this process, cut the plant off about an inch from the ground. Leave the tubers in the ground for a couple of weeks before digging them up. This helps harden up the skin and makes them better for storing.
This is natural die-back and will be different from disease. If you see black spots on the foliage or if the die-off is only affecting some of your plants then you should investigate potato diseases. If the issues are happening before the 20 week mark then it’s also an indication that something is wrong.
Unlike early potatoes, Main crops can be stored away for months at a time. Leave the tubers in the sun to dry out for a few hours before putting them in bags and boxes for storage. Store in a cool garage or shed and make sure to eat the best ones first. A friend once tried to save the best ones for last but by the time he got to them, the mice had already had their turn.