Organic Seed Potato Growing Guide

OEFFA Certified Organic • Certified Disease-Free Seed

We grow and source our seed potatoes to the same standards we expect in our own fields: certified organic, rigorously disease-tested, and ready to thrive in your garden or farm. Follow the steps below for strong plants, healthy yields, and great-tasting potatoes.

When Your Seed Potatoes Arrive

If you’re not planting right away:

  • Remove seed potatoes from plastic bags
  • Store in a cool, dark, well-ventilated space
  • Ideal temperature: 40–55°F

If you’re planting soon:

  • Move potatoes to a slightly warmer area to encourage sprouting (also called “chitting”)

Avoid direct sunlight, which can cause greening.

Soil Preparation

Potatoes perform best in:

  • Loose, well-drained soil
  • High organic matter
  • Light to medium loam is ideal, but potatoes are adaptable

Before planting:

  • Work soil thoroughly
  • Incorporate finished compost or well-aged manure
  • If compost isn’t available, use a balanced organic fertilizer sparingly

⚠️ Too much nitrogen leads to lush vines and fewer potatoes — moderation matters.

Preparing & Cutting Seed Potatoes

  • Large tubers may be cut into egg-sized pieces
  • Each piece must have at least two healthy eyes
  • Allow cut pieces to air-dry and callous for 2–3 days before planting, especially in wetter soils

Smaller seed potatoes should be planted whole.

💡 Tip: If wireworms, maggots, or soil pests are a concern, planting whole seed potatoes can reduce risk.

Yield expectations:

  • Smaller pieces + wider spacing → fewer but larger potatoes
  • Larger pieces + closer spacing → more but smaller potatoes
  • On average, 1 lb of seed yields 5–10 lbs of potatoes

Planting

If you’re not planting right away:

1. Dig a trench 6–8 inches deep
2. Place seed pieces cut side down, eyes up

Spacing guidelines:

  • Standard varieties: 10–12 inches apart
  • Large whole seed: 12–16 inches apart
  • Fingerlings or small varieties: 8–10 inches apart
  • Row spacing: 36 inches (wider spacing makes hilling easier)

    Cover seed potatoes with 3–4 inches of soil, leaving the trench partially open.
    Sprouts typically emerge in 2–3 weeks, depending on soil temperature.

Hilling (Critical Step)

Hilling protects tubers from sunlight and creates ideal conditions for potato formation.

First Hilling

  • When plants reach 8–10 inches tall
  • Pull soil up around stems from both sides
  • Leave only the top leaves exposed

Second Hilling

  • Occurs 2–3 weeks later
  • Add another 2–4 inches of soil

You may

  • Hill twice with soil
  • Or hill once and finish with organic mulch (straw or leaf mulch works well)

Harvest

Potatoes are ready when:

  • Vines yellow, die back, or are killed by frost
  • Tubers have reached full maturity

For best storage:

  • Cut or mow vines 2–3 weeks before harvest to toughen skins

Harvest tips:

  • Dig from both sides of the row using a fork or shovel
  • Avoid puncturing tubers

Potatoes can tolerate light frosts but should be harvested before a hard freeze.

Storage

Store harvested potatoes in:

  • A dark, cool location
  • Ideal temperature: 34–40°F
  • Good airflow is essential

Best containers:

  • Burlap sacks
  • Mesh bags
  • Crates or shallow boxes

Avoid sealed plastic containers.

Approximate Seed Requirements

(Assuming ~2 oz per seed piece)

  • 1 lb of seed plants 5–8 linear feet
  • Based on 12-inch spacing within rows

Our Promise

All seed potatoes from Mad River Garlic Growers are:

  • OEFFA Certified Organic
  • Certified disease-free
  • Carefully handled and stored for planting success

Healthy seed is the foundation of a great harvest — and we’re proud to grow and source seed you can trust.