Knowing when to harvest potatoes in the UK is key to getting the best yield, flavour, and storage quality from your crop. Harvesting too early gives tiny tubers, while waiting too long risks blight, slug damage, or potatoes starting to rot in the ground. This comprehensive guide explains the signs to look for, exact timing for first earlies, second earlies, and maincrop varieties, how to harvest properly, storage methods, and common mistakes — everything you need for a successful potato harvest in UK conditions.
Potato Types and Harvest Timelines
| Potato Type | Planting Time | Weeks to Harvest | Typical Harvest Window (UK) | Ideal Tuber Size | Best Use |
|---|---|---|---|---|---|
| First Earlies | March – early April | 10–12 weeks | Mid-June to mid-July | Hen’s egg size | New potatoes, boiling |
| Second Earlies | March – mid-April | 13–15 weeks | Mid-July to mid-August | Golf ball to tennis ball | Salads, new potatoes |
| Maincrop | April – early May | 15–20+ weeks | Late August to October | Large baking size | Storage, mash, chips |
Note: These are average timings. Warm springs can bring harvests forward by 1–2 weeks; cold or wet summers can delay them.
How to Tell When Potatoes Are Ready to Harvest
Look for these reliable signs:
- Flowering: First and second earlies are usually ready shortly after flowering begins or when flowers start to fade.
- Foliage die-back: Maincrop potatoes are ready when the leaves and stems turn yellow and start to die back naturally.
- Test digging: This is the most accurate method. Gently dig around one plant with a fork (insert it 30 cm away from the stem to avoid spearing tubers). If the potatoes are the right size and the skins are firm (they don’t rub off easily), they are ready.
Tip: For new potatoes (earlies), you can harvest as soon as they reach a usable size. For maincrops intended for storage, wait until the foliage has fully died back for better skin set and longer storage life.
How to Harvest Potatoes Correctly
- Choose a dry day: Harvesting in wet conditions increases the risk of rot and disease spread.
- Use a fork carefully: Insert the fork well away from the plant (at least 30 cm) and lift gently to avoid damaging tubers.
- Lift the whole plant: Shake off excess soil and lay the potatoes on the ground to dry for a few hours (if weather allows).
- Sort the harvest: Separate damaged or green potatoes (green ones contain solanine and should not be eaten).
Regional Variations Across the UK
- Southern & South-East England: Often 1–2 weeks earlier than average due to milder conditions.
- Midlands & East Anglia: Follows the standard timetable closely.
- Northern England, Wales & Scotland: Can be 1–3 weeks later, especially in cooler or wetter years. Maincrops may still be harvested into October or even early November in mild areas.
- Coastal areas: Usually earlier due to warmer soil temperatures.
How to Store Harvested Potatoes
- Curing (for maincrops): Lay them in a single layer in a cool, dark, well-ventilated place for 1–2 weeks to toughen the skins.
- Ideal storage conditions: Cool (4–10°C), dark, and frost-free with good airflow (e.g., hessian sacks, cardboard boxes, or a garage).
- Never store in plastic bags – they trap moisture and encourage rot.
- Check regularly – Remove any sprouting or rotting potatoes immediately.
Common Mistakes to Avoid
- Harvesting too early → Tiny potatoes with thin skins that don’t store well.
- Leaving maincrops in the ground too long → Risk of blight, slug damage, or frost.
- Washing potatoes before storage → This removes the protective skin and encourages rot.
- Storing in light → Causes greening and solanine production (toxic).
What to Do With the Bed After Harvest
Once you have lifted your potatoes, it is important to look after the bed properly to maintain soil health and reduce problems in future seasons. Start by clearing away all the old foliage, stems, and any remaining small tubers — this helps prevent the spread of blight and other diseases that can overwinter in plant debris. Gently fork over the soil to remove any large clumps and to expose any missed potatoes or pests.
At this stage, it is highly recommended to dig in plenty of well-rotted garden compost or manure to replenish nutrients and improve soil structure. Finally, practise good crop rotation by avoiding planting potatoes or any other members of the nightshade family (tomatoes, peppers, aubergines) in the same bed for at least three to four years. This break helps reduce the build-up of soil-borne diseases such as potato cyst eelworm and improves overall yields in the long term.
Conclusion
As you can see, knowing when to harvest potatoes in the UK is not all too difficult once you have gotten the hang of it. Staggering the dates when you plant your potatoes should also ensure you are not overrun with potatoes during harvest season, and you will be able to enjoy your work of labour all year round.
Garden Doctor Tips
“Only harvest what you need at that time, that way the potatoes you leave in the ground will continue to grow!”
“Do a test dig to see if your potatoes are large enough for harvest, if not, give them another 2-3 weeks and they will be ready to go!”
“First earlies make great new potatoes for a spring salad. They will just melt in your mouth!”
“Have some fun and get the kids involved, potatoes are extremely easy to grow and harvesting is fun!”
Frequently Asked Questions
Can you harvest potatoes too early?
If you try and harvest your potatoes too early, they may end up very small and you may have missed out on a larger crop. Just do a simple test dig to see if your potatoes are ready to be lifted. If they are still too small, leave them in the ground for another few weeks where they will grow very quickly.
How long after potatoes flower are they ready?
A good sign of when your early and second early potatoes are ready to be lifted is immediately after the potato flower has faded. A simple test dig will help you discover if they are ready to go. Maincrop potatoes are ready towards the end of summer when the plant has begun to wilt and die.
How do you know when your potatoes are ready to harvest?
There are above-ground tell-tale signs to let you know how your potatoes are getting on. The first earlies and second earlies are ready to harvest once the flower has faded and buds have dropped. Main-crop potatoes are ready towards the end of the summer when the plant has wilted and begun to die back.
Author
Trevor Wright is not just a seasoned horticulturist; he’s the esteemed Garden Doctor. With a BSc in Horticulture and years of hands-on experience in the soil, Trevor has become a trusted mentor for all things gardening. As the founder of Garden Doctor, he’s committed to clarifying the intricacies of gardening, offering straightforward advice that’s rooted in years of practice. His writing is a garden of how-tos, savvy insights, and comprehensive guides that enable individuals to nurture and grow their garden dreams. When he’s not knee-deep in garden beds, Trevor is at his keyboard passing on his green-thumbed wisdom to budding gardeners, ensuring that the legacy of sustainable and joyful gardening blossoms far and wide.
