Potato plants are ready to harvest when their foliage turns yellow and begins to die back. Knowing when to harvest potato plants is key to getting the best yield and flavor from your garden. This guide will walk you through every sign, step, and tip you need to pick your potatoes at the perfect time.
Harvesting too early gives you small, thin-skinned spuds that don’t store well. Waiting too long can lead to rot or pest damage. Let’s find that sweet spot together.
When To Harvest Potato Plants
Timing depends on the potato variety and what you want to use them for. New potatoes are harvested early, while storage potatoes need to stay in the ground longer. The key is watching the plant itself.
Signs Your Potato Plants Are Ready
The most obvious sign is the foliage. When the leaves turn yellow and start to flop over, the plant is sending energy to the tubers. Here are the main indicators:
- Yellowing leaves: The lower leaves turn yellow first, then the whole plant fades.
- Stems dying back: Stems become weak and fall to the ground.
- Flowering: Most potatoes flower before the tubers swell, but not all varieties do.
- Soil cracks: Large potatoes pushing up can crack the soil surface.
New Potatoes vs. Storage Potatoes
New potatoes are harvested early, about 2-3 weeks after the plant finishes flowering. They have thin skins and a sweet, waxy flavor. Storage potatoes need the full growing cycle—wait until the foliage is completely dead, then leave them in the ground for another 2 weeks to toughen the skins.
How To Check Without Digging Up The Whole Plant
You can test a single plant to see if the tubers are ready. Gently dig around the base of one plant with your hands or a small fork. Feel for potatoes of decent size. If they are still tiny, cover them back up and wait another week.
- Choose a plant on the edge of the row.
- Carefully scrape away the top layer of soil.
- Feel for potatoes that are at least the size of a chicken egg.
- If they are small, replace the soil gently.
- If they are good size, harvest that plant and check others.
Different Potato Types Have Different Harvest Times
Not all potatoes mature at the same rate. Knowing your variety helps you plan. Here is a breakdown by type:
First Early Potatoes
These are ready in about 10-12 weeks from planting. They are usually harvested as new potatoes. Look for flowers appearing, then wait 2-3 weeks. Varieties include ‘Swift’ and ‘Rocket’.
Second Early Potatoes
These take about 13-16 weeks. They can be harvested as new potatoes or left to grow larger for storage. ‘Charlotte’ and ‘Maris Peer’ are common second earlies.
Maincrop Potatoes
These are the storage kings, taking 18-22 weeks. Wait until the foliage is completely dead and the skins are firm. ‘Russet Burbank’ and ‘King Edward’ are maincrop varieties.
How To Tell The Difference
Check your seed packet or plant tag. It will say “first early,” “second early,” or “maincrop.” If you lost the tag, count weeks from planting and watch the foliage.
Step-By-Step Harvesting Guide
Once you are sure the potatoes are ready, follow these steps to avoid damaging them. Damaged potatoes rot quickly in storage.
- Stop watering: About 2 weeks before harvest, stop watering the plants. This helps the skins set and reduces rot.
- Cut the foliage: For maincrop potatoes, cut the dead stems down to ground level. Wait 10-14 days before digging.
- Choose a dry day: Harvest when the soil is dry but not baked hard. Wet soil clings to potatoes and can cause bruising.
- Use a garden fork: Insert the fork at the edge of the hill, not directly under the plant. Lever the soil up gently.
- Hand dig: Once the soil is loosened, use your hands to pull out the potatoes. This prevents cuts and bruises.
- Remove debris: Pick off any soil clumps and remove damaged or green potatoes.
What To Do With Green Potatoes
Green potatoes have been exposed to light and contain solanine, which is toxic. Do not eat them. Compost them or throw them away. Keep potatoes covered with soil during growth to prevent greening.
Curing Potatoes For Long Term Storage
If you want to store potatoes for months, curing is essential. Curing heals minor skin damage and thickens the skin. Here is how to do it:
- Temperature: 50-60°F (10-15°C) is ideal.
- Humidity: High humidity, around 85-90%, helps healing.
- Darkness: Keep them in complete darkness to prevent greening.
- Airflow: Good ventilation prevents mold.
- Duration: Cure for 10-14 days.
After curing, move them to a cooler, dark place for long term storage. Ideal storage temperature is 40-45°F (4-7°C). Do not refrigerate, as cold turns starch to sugar and ruins flavor.
Common Curing Mistakes
Do not wash potatoes before curing. Dirt protects them. Also, do not cure in direct sunlight. Use a garage, shed, or dark basement.
Weather And Harvest Timing
Weather plays a big role in when to harvest. If a hard frost is forecast, harvest immediately. Frost can damage tubers near the soil surface. Heavy rain can also cause rot, so harvest before a long wet spell.
How To Handle A Late Blight Outbreak
If late blight hits your plants, harvest right away. Cut off all foliage and remove it from the garden. Dig the potatoes immediately, even if they are small. Blight can spread to tubers if left in the ground.
Do not store blight-affected potatoes. Use them within a few weeks. Discard any that show brown spots or rot.
Tools You Need For Harvesting
You do not need fancy equipment. A few basic tools make the job easier:
- Garden fork: Better than a shovel because it loosens soil without cutting potatoes.
- Gloves: Protect your hands from soil and rough stems.
- Buckets or baskets: Use breathable containers, not plastic bags.
- Soft brush: For removing dry soil after curing.
Why Not Use A Shovel
Shovels cut through potatoes easily. A fork lifts soil and tubers without slicing them. If you only have a shovel, dig wide around the plant.
Storing Potatoes After Harvest
Proper storage keeps potatoes fresh for months. Follow these rules:
- Sort them: Separate any damaged, cut, or diseased potatoes. Use these first.
- Don’t wash: Store them unwashed. Wash only before cooking.
- Use paper bags: Paper breathes better than plastic. Cardboard boxes also work.
- Keep away from onions: Onions release gases that make potatoes sprout faster.
- Check regularly: Remove any that start to rot to prevent spread.
How Long Do Potatoes Last
New potatoes last 1-2 weeks in the fridge. Cured storage potatoes can last 4-6 months in ideal conditions. Check them every few weeks for sprouts or soft spots.
Frequently Asked Questions
Can I Harvest Potatoes After The First Frost?
Yes, but do it quickly. A light frost kills the foliage but tubers underground may be fine. Dig them as soon as possible after a frost to avoid damage.
What If My Potato Plants Never Flower?
Some varieties do not flower, or flowers drop off early. Do not rely on flowers alone. Use foliage color and plant age as your main guides.
How Do I Know If Potatoes Are Too Old To Harvest?
If the foliage has been dead for more than 4 weeks, the potatoes may start to rot or sprout in the ground. Dig them immediately if you see new growth from the tubers.
Can I Harvest Potatoes In The Rain?
It is not ideal. Wet soil makes potatoes muddy and harder to clean. Wait for a dry day if possible. If rain is forecast for a week, harvest anyway to avoid rot.
What Size Should Potatoes Be Before Harvesting?
For new potatoes, any size is fine. For storage, aim for at least 2 inches in diameter. Small ones can be left to grow if the season allows.
Troubleshooting Common Harvest Problems
Even with good timing, issues can arise. Here is how to handle them:
Potatoes Are Too Small
This usually means you harvested too early, or the plants were crowded. Next year, space plants 12 inches apart and water consistently. If you dig a test plant and find small potatoes, wait another 2 weeks.
Potatoes Have Holes Or Chewed Areas
Wireworms or voles may be the cause. Wireworms are small, thin worms that tunnel into tubers. Voles chew larger holes. Remove affected potatoes and do not store them. Use traps or beneficial nematodes for control next season.
Potatoes Are Splitting Or Cracking
Irregular watering causes cracks. If you water heavily after a dry spell, potatoes swell too fast and split. Water evenly throughout the growing season. Split potatoes are still edible but do not store well.
Can You Eat Split Potatoes
Yes, but use them within a few days. The cracks allow bacteria to enter, so they rot faster. Cut away any discolored parts before cooking.
Final Tips For Perfect Potato Harvest
Harvesting at the right time is a balance of patience and observation. Here are my last pieces of advice:
- Mark your calendar when you plant. Count forward the weeks for your variety.
- Dig a test plant every week once the foliage starts yellowing.
- Harvest on a sunny, dry day for easiest cleaning.
- Handle potatoes gently—bruises lead to rot.
- Store only the best ones. Eat damaged potatoes first.
Potato plants are ready to harvest when their foliage turns yellow and begins to die back. Trust that signal, and you will have a bountiful, tasty crop. Happy harvesting.