How to Grow Potatoes UK
How to Grow Potatoes UK: The Ultimate 2025 Guide
Key Takeaways: Potato Growing Essentials
- ✅ Choose the Right Variety: Earlies for speed and salads; Maincrops for bulk storage and roasting.
- ✅ Chit for Success: Start chitting in potting sheds 6 weeks before planting to boost yields.
- ✅ Don't Forget to Earth Up: Essential for preventing green tubers and maximizing your crop count.
- ✅ Watch for Blight: Warm, humid UK summers are blight triggers—water at the base, not the foliage.
- ✅ Use Your Glass: Start earlies in lean-to greenhouses in February for a harvest weeks ahead of neighbours.
Is there anything more satisfying than digging for "buried treasure" in your own garden? I don't think so. Whether you're dreaming of buttery new potatoes with your Sunday roast or massive baking potatoes for a winter comfort meal, learning how to grow potatoes UK style is a rite of passage for every gardener.
In our 16+ years helping UK gardeners at Greenhouse Stores, potatoes remain the number one crop our customers ask about. Why? Because the taste of a home-grown spud—dug up minutes before cooking—is completely different to the plastic-wrapped bags at the supermarket.
However, the UK climate can be tricky. From late frosts to the dreaded blight, you need a solid plan. In this guide, I'll walk you through everything we've learned about growing bumper crops, whether you have a massive allotment, a small patio, or just a greenhouse corner.
Understanding Potato Types: Earlies vs. Maincrop
Before you buy your seed potatoes, you need to know what you're actually growing. In the UK, we categorise them by how long they take to mature.
First Earlies
These are the sprinters. Plant them around late March, and they'll be ready in 10-12 weeks (June/July). They are smaller, waxy "new potatoes"—perfect for salads.
- Why grow them: They are usually harvested before blight becomes a major issue in the UK summer.
- Top Pick: 'Rocket' or 'Swift'.
Second Earlies
These take about 13-15 weeks. You plant them mid-April for a July/August harvest. They are slightly larger than first earlies but still excellent salad potatoes.
- Top Pick: 'Charlotte' or 'Maris Peer'.
Maincrop
The marathon runners. Planted mid-April, these take 20 weeks+ and are harvested Aug-Oct. These are your big bakers and roasters that you store for winter.
- Why grow them: Huge yields and storage potential.
- Top Pick: 'King Edward' or 'Maris Piper'.
When to Plant Potatoes in the UK
Timing is everything. Plant too early outside, and frost will blacken the shoots. Plant too late, and you miss the growing window.
| Variety | Plant Outdoors | Harvest | Greenhouse Planting (Forcing) |
|---|---|---|---|
| First Earlies | Late March | June/July | February |
| Second Earlies | Mid-April | July/Aug | March |
| Maincrop | Mid-April | Aug-Oct | N/A (Too big) |
If you are looking to get a head start, check out our greenhouse growing guide. Using glass allows you to plant earlies in bags as early as February, protecting them from frost while the soil warms up.
Preparation: Chitting Your Potatoes
"Chitting" sounds technical, but it just means encouraging the seed potato to sprout before planting. This is especially important for Earlies to get them off to a flying start.
How to Chit:
- Timing: Start about 6 weeks before planting (late Jan/early Feb).
- Location: Place your seed potatoes in egg boxes or chitting trays.
- Position: Stand them "rose end" up (the end with the most eyes).
- Environment: Keep them in a cool, light, frost-free place. A potting shed bench is ideal, or a bright windowsill in a cool room.
Matt's Tip: You want short, stubby green shoots (about 2cm long). If they are long, white, and spindly, it means they aren't getting enough light.
Planting Method 1: The Greenhouse "Head Start" (Winter Planting)
This is a method many competitors overlook, but it's a game-changer if you own a greenhouse. By planting in late winter (Jan/Feb), you can be eating new potatoes in May.
- Use Containers: Use 30L pots or robust potato bags.
- Compost Mix: Use a peat-free multi-purpose compost mixed with a handful of potato fertiliser.
- Planting: Place 3 chitted tubers halfway down the bag and cover with compost.
- Protection: Keep them in the greenhouse. If a hard frost is forecast, throw some horticultural fleece over the bags.
- Watering: Keep the compost moist but not sodden. Rot is the enemy in winter.
This method also frees up your greenhouse floor space in time for growing tomatoes in summer!
Planting Method 2: Growing in the Ground
If you have an allotment or large veg patch, growing in the ground is the most cost-effective way to get a massive harvest.
- Prepare the Soil: Dig over the soil in winter. Potatoes love rich soil, so dig in plenty of well-rotted manure or compost.
- Dig Trenches: Dig a V-shaped trench about 12cm (5in) deep.
- Spacing:
- Earlies: 30cm (12in) apart, rows 45cm (18in) apart.
- Maincrop: 37cm (15in) apart, rows 75cm (30in) apart.
- Plant: Place tubers with shoots facing up. Handle gently to avoid snapping the shoots.
- Cover: Carefully rake the soil back over the trench to cover the tubers.
Planting Method 3: Containers and Bags (Small Spaces)
No garden? No problem. Potatoes thrive in bags on patios or balconies.
- The Container: You need at least 30cm depth. Specialised potato bags are great because they fold away in winter.
- Drainage: Ensure there are holes in the bottom. Add a layer of gravel if using a plastic pot.
- The Layering Technique:
- Fill the bottom 10cm with compost.
- Place 3 tubers (for a 30-40L bag).
- Cover with another 10cm of compost.
- Wait: As the green shoots appear, keep adding more compost ("earthing up") until you reach the top of the bag.
Pro Tip: Don't overfill the bag with seed potatoes. 3 tubers in a standard bag will yield more total weight than 5 tubers, which will just compete for space and stay small.
Essential Care: Earthing Up, Water, and Feed
Earthing Up
Whether in bags or trenches, you must "earth up." As the stems grow, draw soil up around them to create a ridge.
- Why? It protects shoots from late frosts.
- Crucial: It stops the developing tubers from being exposed to light. Light turns potatoes green and poisonous.
Watering
Potatoes are thirsty plants, specifically when the tubers are starting to swell (usually just after flowering).
- Ground: Water heavily once a week in dry spells rather than a light sprinkle every day.
- Containers: These dry out fast. In hot UK summers, you might need to water daily.
Feeding
- Ground: If you manured the soil, you might not need extra feed.
- Containers: The compost nutrients run out after 6 weeks. Use a liquid high-potash feed (tomato feed works well) every fortnight once foliage is established.
Dealing with Pests and Diseases
Potato Blight
This is the big one for UK growers. It's a fungal disease spread by wind in warm, humid weather (often called "Smith Periods").
- Symptoms: Brown patches on leaves surrounded by a pale halo. Tubers turn to reddish-brown mush.
- Prevention: Water the soil, not the leaves. Ensure good airflow. Grow First Earlies (harvested before blight hits).
- Cure: There is no cure. If blight hits, cut all foliage down immediately to ground level to stop it travelling to the tubers. Wait 2 weeks, then dig up the potatoes.
Slugs
Slugs love tunneling into maincrop potatoes.
- Solution: Nematodes are the best organic defence. Apply to the soil in spring.
Harvesting and Storage
When to Harvest
- Earlies: Wait until flowers open or buds drop. Have a gentle "furtle" (dig) with your hand to check the size. Harvest as needed.
- Maincrop: Wait until the foliage turns yellow and dies back. Cut the foliage down and leave the potatoes in the ground for 10 days. This sets the skins, making them better for storage.
Storing Your Crop
Once dug up, let them dry on the surface for a few hours (but not in direct sun). Store them in hessian sacks or paper bags—never plastic, or they will sweat and rot. Store in a cool, dark, frost-free place. A potting shed or garage is usually fine, provided it doesn't freeze. Check them regularly and remove any that have gone soft.
Why not try growing grow garlic in the space you've just cleared? It's a great follow-on crop for late autumn planting.
Summary
Growing potatoes in the UK is a rewarding cycle that can keep your kitchen stocked for months. Whether you are forcing early crops in one of our greenhouses or filling a raised bed with maincrops, the principles remain the same: prepare the soil, protect from frost, and keep them watered.
Ready to get started? Get your seed potatoes ordered, clean out your pots, and look forward to that first buttery bite of a home-grown roastie.
Frequently Asked Questions
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What is the best month to plant potatoes in the UK?
For outdoor planting, late March to mid-April is ideal, once the risk of heavy frost has passed. However, if you are growing in a greenhouse, you can plant First Earlies as early as February for a crop in May.
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Do I really need to chit potatoes?
For First and Second Earlies, yes—it definitely speeds up the harvest. For Maincrops, modern trials suggest it makes less difference to the final yield, but many traditional gardeners (ourselves included) still do it to check the tubers are viable before planting.
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How many potatoes do you get from one plant?
This depends on the variety and space. Generally, one seed potato will produce about 1kg of harvest. In a grow bag with 3 tubers, expect around 2-3kg of potatoes if watered and fed correctly.
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Can I grow potatoes in supermarket bags?
Technically yes, "bags for life" are strong enough, but you must punch plenty of drainage holes in the bottom. If water pools in the bag, the potatoes will rot. Dedicated potato growing bags are usually deeper and have easier access flaps for harvesting.
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How often should I water potatoes in bags?
Potatoes in bags rely entirely on you for water. In spring, check every 2-3 days. In the height of summer, check daily. If the compost pulls away from the side of the bag, it is too dry. Consistent moisture prevents "scab" on the potato skins.
