How to Plant Potatoes in Trenches

Planting potatoes in trenches is the traditional and most widely used method in UK gardens and allotments. It’s ideal for growing all types of potatoes, especially maincrop varieties, and makes earthing up easy while producing reliable yields.

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• Seed Potato Collection (Early, First & Second Earlies)
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• Potato Grow Bags / Containers
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• Potato Fertiliser / Soil Booster
Specially formulated feed to support healthy tuber development and improve yields — apply at planting or as a top-dress during the season.
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• Potato Planting Guides & Markers
Helpful tools and guides that take you through planting depth, spacing, and care — plus reusable markers to keep track of different varieties.
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Why Plant Potatoes in Trenches?

Trench planting:

• Improves drainage in heavier soils
• Makes earthing up simple
• Encourages strong root and tuber development
• Produces good yields
• Works well for large potato crops

It’s particularly useful on allotments and larger garden plots.

Step 1: Choose the Right Site

• Select a sunny, open position
• Avoid ground that is waterlogged
• Rotate crops yearly to reduce disease

Potatoes grow best where legumes or brassicas were grown the previous year.

Step 2: Prepare the Soil

• Remove weeds and stones
• Dig over the area
• Incorporate well-rotted compost or manure
• Avoid fresh manure, which can cause scab

The soil should be loose and free-draining.

Step 3: Dig the Trenches

• Dig trenches 10–15 cm deep
• Space trenches according to potato type:
  • First earlies: 60 cm apart
  • Second earlies: 60–65 cm apart
  • Maincrop: 70–75 cm apart

Place the excavated soil to one side for earthing up later.

Step 4: Add Organic Matter (Optional)

For extra nutrition:

• Add a thin layer of compost or manure to the trench base
• Lightly mix with soil

This feeds the plants as they grow.

Step 5: Plant the Seed Potatoes

• Place seed potatoes in the trench
• Shoots (chits) facing upwards
• Spacing between potatoes:
  • First earlies: 30 cm
  • Second earlies: 30 cm
  • Maincrop: 35–40 cm

Do not overcrowd.

Step 6: Cover the Potatoes

• Gently cover seed potatoes with soil
• Leave the trench level with the surrounding ground
• Lightly firm the soil

Do not compact the soil heavily.

Step 7: Water If Needed

• Water lightly if soil is dry
• Do not water if soil is already moist

Avoid waterlogging, especially early in the season.

Step 8: Protect from Frost

When shoots emerge:

• Earth up soil over shoots if frost is forecast
• Or cover with horticultural fleece

Early potatoes are particularly vulnerable to frost.

Step 9: Earth Up as Plants Grow

Earthing up is essential when trench planting.

• Draw soil from either side of the trench up around stems
• Leave the top leaves exposed
• Repeat as plants grow
• Build ridges up to 20–25 cm high

This protects tubers from light and improves yield.

Step 10: Ongoing Care

• Water during dry spells
• Keep trenches weed-free
• Check regularly for pests and disease

Watering is most important during flowering and tuber formation.

Step 11: Harvesting Trench-Grown Potatoes

• First earlies: Harvest when flowering begins
• Second earlies: Harvest just after flowering
• Maincrop: Harvest when foliage has died back

To harvest:

• Use a fork to gently lift from the side of the ridge
• Work carefully to avoid damaging tubers

Common Mistakes to Avoid

• Planting into cold, wet soil
• Digging trenches too deep
• Skipping earthing up
• Overcrowding seed potatoes

Trench Planting vs Other Methods

• Trenches: Best for large crops and maincrop potatoes
• Raised beds: Better drainage, easier access
• Containers: Best for small spaces

Quick Summary

• Trench depth: 10–15 cm
• Plant spacing: 30–40 cm
• Row spacing: 60–75 cm
• Earth up to 20–25 cm
• Water during dry spells

Final Tip

Trench planting is a proven, reliable method for growing potatoes. With correct spacing, regular earthing up, and steady watering, trench-grown potatoes can produce some of the best yields in the garden.