When to plant late potatoes: May through June

Why late potatoes?

Late potatoes are what their name says: varieties you plant later in the season and harvest in autumn. They need a much longer growing period (120-150 days), but because of that time they grow larger, develop thicker skin, and store better. They are ideal for autumn storage and winter feeding.

The advantage: you have large, well-filled potatoes in October-November that you can store in a cool cellar for four to six months. This gives you food until February-March.

The risk: because you plant so late, you must be extra careful about nutrient loss and disease in summer. Foliage can get mildew in wet summers.

Cultivars: 'Bintje', 'Russet', 'Desiree', 'Kennebec'.

Timing: when to start?

You plant late potatoes much later than early varieties. Because they need longer to grow, you plant them after the Ice Saints have passed but before summer drought hits:

• South Netherlands/Belgium: early May (around May 5-8)
• Central Netherlands: second week of May (around May 12-15)
• North Netherlands: third week of May (around May 20-22)

In no case do you plant later than late May. After that the plant does not mature enough.

The rule: plant between the Ice Saints passing (May 13) and late May. In practice: mid-May is ideal for all Benelux.

Character of late varieties

Late variety traits:

• Growing period: 120-150 days
• Tuber size: large (100-250 grams each)
• Skin thickness: thick, rough
• Flavor: varies, slightly earthy or nutty
• Storage: 4-6 months at 5-8 degrees

Bintje:

• Dutch classic, yellow, firm flesh
• Fine flavor, universally usable
• Great for storage

Russet:

• Brown skin, white flesh
• More mealy than Bintje, good for chips
• Also storage-worthy

Desiree:

• Red skin, yellow flesh
• Juicy, tender, fine
• Also storage-capable

Kennebec:

• Yellow, firm, slightly drier
• Classic for fries
• Prime long-term storage

For home storage you would pick Bintje or Kennebec for their storage length.

Preparation of late potato ground

Late potatoes need a bit more feeding than early varieties (because they grow longer). Preparation:

Per square meter:

• Work in 4-5 liters garden compost, 20 cm deep
• Add phosphate-rich fertilizer (bone meal, slug pellets)
• Make soil smooth and level
• Check soil did not grow potatoes last year

Late potatoes love potassium (firmness, storage). Give handfuls of potassium nitrate at planting (smoke-free, no mildew later).

Planting method: in ridges

Plant late potatoes the same way as early varieties, but with slightly more spacing (because they grow larger).

1. Make groove 10-12 cm deep.
2. Set seed potatoes with 40-45 cm spacing (versus 30-35 cm for early varieties).
3. Put moist garden compost around the potato.
4. Cover with earth, build up into a ridge 15-20 cm.
5. Press gently without compacting.

Larger spacing gives more food per plant and thus larger tubers.

Growth and summer care

Late potatoes need feeding and moisture all summer:

Feeding:

• Give feeding every two weeks (nitrogen-rich) through late July
• Stop feeding from August (too much foliage, tuber grows less)
• Use tomato fertilizer or vegetable fertilizer

Water:

• Grow best with constantly moist soil
• Water when top 5 cm feels dry
• In dry summer: two liters per plant per week
• More water equals more tuber size

Diseases:

• Powdery mildew (powder on leaf): goes away with rain
• Late blight (brown patches on foliage): remove affected leaves
• Colorado beetle: watch in May-June, remove by hand

The foliage stands large from June through September. No more late frost risk.

Harvest preparation

Harvesting late potatoes happens in October-November once foliage dies.

Signs foliage is stopping:

• Leaves yellow and brown
• Leaves fall off
• Stems become purple-green and limp
• This normally happens late September through early October

Wait until foliage completely dies (even from just one plant) before digging. This gives time for skin to thicken.

Harvesting and storage

Harvesting:

1. Wait until foliage is completely gone
2. Dig carefully from outside of plant toward center (not straight down).
3. Loosen earth gently, do not strike with spade (damage occurs).
4. Collect large potatoes and discard any damaged ones.
5. Let potatoes dry in sun (2-3 hours) so earth dries and falls off.

Storage:

• Select large, unblemished potatoes (no cracks, dents, cuts)
• Damaged potatoes eat fresh (they rot quickly)
• Put stored potatoes in dark, ventilated box (no plastic bags, they sweat)
• Temperature: 5-8 degrees (cool cellar ideal)
• Ventilation: check condition every two weeks
• Duration: 4-6 months
• Check monthly: remove rotten potatoes immediately

Frequently asked questions

Can I plant late and early potatoes at the same time?

No, not practical. They have very different growing periods. Early varieties are ready in June-July, late varieties in October. Plant them separately in your garden.

How long can I eat late potatoes?

With good storage (5-8 degrees, dark, ventilated): four to six months. This means October through March. In April they usually sprout and rot quickly.

Can I use my own potatoes for next year?

No, not recommended. Self-used potatoes (actually: seed potatoes) accumulate disease after a few years. Buy new certified seed each year. This yields much better crop.

Why is my late crop full of Colorado beetles?

Colorado beetles get worse in July-August. Late potatoes grow large just then and attract them. Check weekly for beetles and larvae. Hand-picking is best (no poison, better for environment). A few beetles harm little.

How long does harvesting take?

Early harvesting is possible if careful (see earlier article on early varieties). With late varieties: usually you wait until foliage dies. This can be October.

Step-by-step

Step 1: Choose location and variety

Choose ground where potatoes did not grow last year. Choose late variety (Bintje, Kennebec).

Step 2: Preparation

Work in compost and potassium. Make smooth and level.

Step 3: Plant mid-May

Plant between Ice Saints passing and late May. Mid-May ideal.

Step 4: Summer care

Water in dry spells. Feeding through late July. Check for disease.

Step 5: Harvest October

Wait until foliage dies. Dig carefully. Dry potatoes. Sort and store.

Discover your own garden design

At [gardenworld.app](https://gardenworld.app) you can upload your front yard and see where your late potato bed fits. With four to six months of storage you have food until spring.