Kennebec Potato - 2 Pound Bag

Potatoes are a wonderful crop to grow at home. They produce large yields that keep longer than some soft vegetables like tomatoes or cucumbers. Potatoes are easy to grow and maintain with the proper care. It’s important to note that growing potatoes does require some unique care that other crops don’t so read on for tips on how to grow potatoes.

Growing Potatoes

The easiest way to grow potatoes is from seed potatoes. True seed potatoes are certified virus indexed and some even come from the tissue’s culture, guaranteeing a clean seed potato to start your crop. If you’ve ever left potatoes in your pantry too long, you may have noticed them sprouting.  While you might be tempted to use these as seed potatoes, you will encounter more disease and virus issues that will reduce your yield, if not eliminate it altogether. We recommend buying seed potatoes for greater success. You’ll also accelerate your time to harvest over starting with potato seeds.

Depending on where you live, most gardeners can plant potatoes between March and May for a late summer or fall harvest. To find the ideal time to plant seed potatoes in your growing zone, refer to the chart below. Always check your frost dates to avoid planting potatoes before the last hard frost.

Planting Dates for Potatoes by Zone

Seed potatoes from Park Seed are of a consistent, small size and do not need cutting. In fact, our grower’s recommend small tubers for best results as cutting can promote disease. If you must cut them due to size, plan on cutting sprouted potatoes to the size of a chicken egg 1 to 2 days before you plant them. Place cut potatoes in a well-ventilated space so the cut edges can create a callus. The callus may help to ward off rot once you put the potato piece into the ground.

Planting Seed Potatoes

Potatoes can be planted relatively early in your Zone’s growing season as they prefer cooler (not cold) weather. Once the threat of frost has passed, you can plant your seed potatoes. If you have a late or unexpected frost, simply mulch over the foliage or use a row cover or old sheet to protect the plants. Be sure to remove any mulch or artificial covering the morning after.

Seed potatoes can be planted once the soil temperature is above 45°F. The ideal soil temperature for growing potatoes is 45-55°. Your potatoes thrive in full sun—at least six hours of direct sunlight daily. Potato plants also need a fair amount of growing space. Plan on spacing potato rows three feet apart.

Working with loose garden soil, dig V-shaped trenches roughly 8 inches deep into the soil. The trench should be approximately 3 inches wide at the bottom and 6 inches wide at the surface. The easiest way to do this is to drag a pointed shovel through the worked soil.

Add manure or compost to the bottom of the trench. Place the potato pieces into the trench, eyes facing up (cut side down if using cuts potatoes). Space the seed potatoes 4 inches apart. Once your trench is full, cover the potato pieces with 4 inches of soil. If your soil is rocky, lay the potato pieces on the ground and build the soil up over the potato rather than cutting down into the soil.

Once the potatoes sprout, in about two weeks, you’re ready to start hilling the potatoes.

Hilling Potatoes

Potatoes are a tuber. A tuber is a unique type of root, which is why potatoes grow underground. As the plant grows up, more tubers are formed. Without hilling, potatoes would eventually develop above the soil level. Hilling is best done first thing in the morning.  Potato plants are upright in the morning and tend to droop as the day goes on.

Potatoes that are exposed to the sun for too long will develop a toxin called solanine and turn green in color. Solanine makes potatoes bitter and inedible and, if ingested, can cause nausea. Hilling keeps the growing potatoes covered and protected from overexposure to the sun.

Hilling potatoes is easy to do. Add soil around the base of the potato plant to keep only the top part of the plant exposed. As the potato plant grows upward, it will develop additional tubers from secondary stems along the main stem. Hilling keeps those new potatoes covered.

After planting potatoes, it will take about two weeks before sprouts emerge depending on the variety of potato. If you planted the seed potatoes in trenches, you’ll fill in the rest of the trench with 3 to 4 inches of soil as the sprouts emerge, keeping only the top of the sprouts uncovered.

From this point, plan on hilling the potatoes every time the plants are 10 to 12 inches tall. Continue to build the soil up around the plant, keeping the base of the stem covered and any potatoes covered. The last time that you’ll hill your potatoes should be before they bloom.

Caring for Potatoes

Potatoes need 1 to 2 inches of water each week. Keep the soil evenly moist, especially after the plants emerge. Soil that is soggy can cause misshapen potatoes, while soil that is too dry will cause a small crop.

Potato plants require a high level of nutrients and prefer to grow in cooler soil. So be sure to add compost around the potato hills and in between the rows. This will help to cool the soil, keep moisture levels consistent, and provide the nutrients your growing potatoes need.

Potatoes are hardy but can be susceptible to a few issues. The most common diseases are potato scab and blight. The most common pest that attacks potatoes is the Colorado potato beetle.

Potato scab is generally caused by soil that has a high pH level also known as alkaline soil. A pH level higher than 5.2 makes your potato crop susceptible to developing potato scab. To help prevent this, plant potatoes in acidic soil. You can also dust them with sulfur before planting.

The Colorado potato beetle is a small (1 centimeter) beetle that is brightly colored with a yellow and cream-colored body with black stripes. They’re aptly named because they love potato plants. If you see them, pick them off and drop them into insecticidal soap. Birds will also help by picking them off your plant. Nymphs can be treated with diatomaceous earth.

Practice crop rotation in your garden. Avoid planting root crops in the same spot right after potatoes. Instead, plant a legume, like beans, that will add nitrogen back to the soil.

Harvesting Potatoes

Most potatoes are ready to harvest once the foliage starts to die back. An exception to this is new potatoes. New potatoes are potatoes that are harvested early so they have thin skins and tender flesh. Harvest new potatoes 2 to 3 weeks after the plants bloom.

To harvest regular potatoes, wait until the top of the plant has died completely. Cut off the dead tops of the plants and leave them alone for at least 10 days. This encourages the potatoes to develop a thick skin. If the soil is soggy, remove the potatoes right away as soggy soil can cause the potatoes to rot.

On a dry day, dig up a test hill. Rub the potato with your fingers to feel the skin. If the skin rubs off easily, leave the potatoes in the ground for a few more days. If the skin feels tough and doesn’t rub off, you can harvest your potatoes.

Dig them up as gently as possible. You can use a shovel, just be careful not to stab into the potatoes. If you do cut or scar some, use them first as they won’t last as long in storage. The hilled soil should be loose, making it easy to get the potatoes up.

Potatoes that have been dug up shouldn’t be left in the sun for extended periods of time. Lay the harvested potatoes out just long enough for them to dry. Once they are dry, brush off excess dirt, and store them. Remember, leaving potatoes in the sun can cause them to turn green and develop the toxin solanine.

Tips for harvesting potatoes:

• If you want new potatoes, harvest them 2 to 3 weeks after the plants bloom. Don’t cure new potatoes. Instead, plan on using them quickly after harvesting.
• Potatoes prefer cool weather but can’t handle a hard frost. If you know that a hard frost is coming, harvest your potatoes.
• You can encourage a thicker skin (and longer shelf life) on your potatoes by cutting back on how much water you give them after mid-August. 

Carrie with From Seed to Spoon shows us how she grows and harvests potatoes in Smart Pots®. Great idea, Carrie!

Curing and Storing Potatoes

Potatoes need to cure before being stored. To cure potatoes, store them in a cool, dark, and dry spot for 7 to 10 days. Curing potatoes causes them to develop an even thicker and more robust skin, which will help them to store longer. You can brush off any soil that is stuck to the potatoes, but don’t wash them until right before you use them. Washing potatoes shortens their shelf life significantly.

To store potatoes, you’ll need to have a dedicated space for them. You can store potatoes in your home for a short period of time, but it’s generally too warm for long-term storage. Potatoes can sprout when kept indoors. Avoid storing potatoes near onions (or apples) as they produce and release ethylene gas that can cause potatoes to rot.

Store potatoes in a cool, dark, humid, well-ventilated space. Potatoes should be stored in temperatures between 45-55° to prevent sprouting and disease. Humidity is key. Potatoes are 80% water and will quickly dry out and shrivel up if there isn’t enough moisture in the air. A dark space will prevent the potatoes from turning green. After potatoes are harvested, they still use oxygen and release carbon dioxide, so it’s important that they always have fresh air.