When Are Potato Plants Ready to Harvest?
Potato plants are ready to harvest at different stages depending on the type of potato you’re growing and whether you want to harvest “new” potatoes for immediate consumption or mature potatoes for storage. Harvesting can begin a few weeks after flowering for new potatoes, and several weeks after the plant dies back for mature potatoes.
Understanding Potato Growth
Potatoes, a staple food worldwide, are modified stems called tubers that grow underground. Knowing how these tubers develop helps you determine the optimal harvest time. The potato plant’s growth cycle can be divided into stages, impacting when it’s best to dig up your crop.
- Sprout Development: The initial stage, where sprouts emerge from the seed potato.
- Vegetative Growth: The period focused on foliage development, where the plant establishes its above-ground structure.
- Tuber Initiation: When small tubers begin to form underground. This often coincides with the start of flowering.
- Tuber Bulking: The tubers rapidly increase in size, drawing energy from the plant.
- Maturation: The plant slows down, and the skin of the tubers thickens, preparing them for storage.
Deciding on Your Harvest Goal: New vs. Mature Potatoes
The primary factor influencing harvest time is whether you desire new potatoes or fully mature ones. This depends largely on your intended use for the potatoes.
- New Potatoes: These are harvested early, offering a tender skin, delicate flavor, and smaller size. They’re best enjoyed fresh and don’t store well.
- Mature Potatoes: Left in the ground longer, they develop a thick skin suitable for long-term storage. Their flavor is more robust, and their size is larger.
Harvesting “New” Potatoes
For that tender, early-season flavor, new potatoes are the way to go.
- Timing: Begin checking for new potatoes 2-3 weeks after the plant finishes flowering.
- Method: Carefully dig around the base of the plant, feeling for small tubers. Gently remove the desired number without disturbing the rest of the plant.
- Characteristics: New potatoes will have thin, easily rubbed-off skins and a creamy texture.
- Storage: Eat them as soon as possible, as they don’t store well. Refrigerating them can extend their life by a few days.
Harvesting Mature Potatoes for Storage
For longer-term use, mature potatoes are the answer.
- Timing: Wait until the potato plants have completely died back. This signals that the tubers have reached maturity and their skins have hardened. Allow an additional 2-3 weeks after die-back for the skins to fully cure in the soil.
- Method: Use a garden fork to carefully lift the plants and dig up the potatoes. Avoid damaging the tubers during the process.
- Characteristics: Mature potatoes will have thick, firmly attached skins.
- Curing: After digging, spread the potatoes out in a dark, well-ventilated place for 1-2 weeks to allow their skins to further cure and harden.
- Storage: Store cured potatoes in a cool, dark, and well-ventilated place (ideally between 40-50°F or 4-10°C).
Signs Your Potato Plants Are Ready
Observing your plants for these signs can help you determine the ideal harvest time.
- Flowering: Indicates tuber initiation; new potatoes will be ready a few weeks later.
- Yellowing Foliage: A sign of the plant slowing down and tubers maturing.
- Die-Back: The complete death of the above-ground foliage signifies that the tubers are fully mature and ready for harvest.
The Harvesting Process: Step-by-Step
Here’s a step-by-step guide to harvesting your potatoes:
- Prepare: Gather your tools: a garden fork, gloves, and containers for collecting the potatoes.
- Loosen the Soil: Gently loosen the soil around the potato plants with the garden fork, being careful not to puncture any tubers.
- Lift the Plants: Carefully lift the plants from the ground, using the fork to help dislodge the potatoes from the soil.
- Collect the Potatoes: Pick up the potatoes by hand, brushing off any excess soil.
- Inspect for Damage: Check the potatoes for cuts, bruises, or signs of disease. Discard any damaged or diseased potatoes.
- Curing (for Mature Potatoes): Spread the harvested potatoes in a dark, well-ventilated area for 1-2 weeks to cure.
Common Mistakes to Avoid
- Harvesting too Early: Harvesting before the tubers have matured results in smaller, less flavorful potatoes that don’t store well.
- Damaging the Potatoes: Carelessly digging can cut or bruise the tubers, making them susceptible to rot.
- Storing Potatoes in Direct Sunlight: Exposure to sunlight can cause potatoes to turn green and produce solanine, a toxic alkaloid.
- Storing Damaged Potatoes: Damaged potatoes can rot and spread disease to healthy potatoes during storage.
- Ignoring Soil Moisture: Avoid harvesting when the soil is excessively wet, as this can promote fungal diseases. Wait for a dry spell before digging.
Potato Variety and Harvest Timing
Different potato varieties mature at different rates. Here’s a general guide:
| Variety | Maturity (Days) | Recommended Use |
|---|---|---|
| Yukon Gold | 80-90 | Boiling, Baking, Roasting |
| Red Pontiac | 70-80 | Boiling, Salads |
| Russet Burbank | 100-130 | Baking, Frying |
| Fingerling | 90-110 | Roasting, Salads |
| Kennebec | 90-100 | Frying, Baking |
Frequently Asked Questions (FAQs) About Potato Harvest
How can I tell the difference between a new potato and a mature potato?
A new potato has thin, easily rubbed-off skin. It’s also generally smaller in size. A mature potato has thick, firmly attached skin and is significantly larger.
What happens if I harvest potatoes too early?
Harvesting too early yields smaller potatoes with thin skins that are more prone to damage and don’t store well. The flavor is also less developed.
Can I leave potatoes in the ground over winter?
Generally, it’s not recommended to leave potatoes in the ground over winter, especially in areas with freezing temperatures. The potatoes can freeze and rot, rendering them inedible.
How do I store potatoes after harvesting them?
Store cured potatoes in a cool, dark, and well-ventilated place (ideally between 40-50°F or 4-10°C). Avoid storing them near apples or bananas, as these fruits release ethylene gas, which can cause potatoes to sprout prematurely.
Why are some of my potatoes green?
Potatoes turn green when exposed to light. The green color is due to the production of solanine, a toxic alkaloid. Green potatoes should not be eaten.
What does “curing” potatoes mean?
Curing involves spreading freshly harvested mature potatoes in a dark, well-ventilated area for 1-2 weeks. This process allows the skins to harden and heal any minor injuries, which improves their storage life.
Can I harvest potatoes after a frost?
It’s best to harvest potatoes before a hard frost. If frost is imminent, harvest mature potatoes immediately. If the ground freezes, the potatoes will likely be damaged.
What are “volunteer” potatoes, and should I harvest them?
Volunteer potatoes are potatoes that grow from tubers left in the ground from a previous harvest. If they are in a convenient location, you can certainly harvest them, following the same guidelines for new or mature potatoes.
How deep do I need to dig to find the potatoes?
Potatoes typically grow within the top 6-12 inches of soil. The depth can vary slightly depending on the potato variety and soil conditions.
My potato plants flowered, but I don’t see any potatoes. What’s wrong?
Sometimes potato plants flower but don’t produce many tubers. This can be due to various factors, including poor soil fertility, inadequate watering, or high temperatures. Ensure your plants have sufficient nutrients and water, and consider providing shade during extremely hot periods.
Can I eat potato sprouts?
It is not recommended to eat potato sprouts, as they contain solanine and are potentially toxic. It’s best to remove the sprouts before cooking the potatoes.
What do I do with diseased potato plants?
If your potato plants show signs of disease (e.g., blight), it’s important to remove and destroy them immediately to prevent the spread of the disease to other plants. Do not compost diseased plant material.