Potato Growing Guide
Potatoes from seed? Yes indeed! Growing potatoes from seeds (often called “true potato seed” or TPS), instead of tubers, means each plant is genetically different, rather than a clone, adding diversity to the garden. If you were wondering how to grow potatoes from seed, you’ve come to the right place!
When to Sow Outside: Garden potatoes can be planted as soon as the soil can be worked. For many gardeners, this is about 2 weeks after the last spring frost.
In warmer regions, potatoes can be grown as a winter crop and planting times range from September to February.
The soil should not be so wet that it sticks together and is hard to work. Let it dry out a bit first.
Potatoes also do well in large containers and grow bags.
Potatoes like to grow in fertile, loose, well-drained, somewhat sandy soil; hard or compacted soil leads to misshapen tubers. Ideally, the soil should be slightly acidic (pH 5.8 to 6.5) and the soil temperature is at least 45º to 55ºF (7° to 13°C). Before planting (preferably in the fall), mix compost or organic matter into the soil when growing in the garden.
Potatoes can be grown in barrels, large containers, grow bags or even 5-gal buckets.
when growing in containers, drainage becomes very important to prevent the roots and/or tubers from rotting.
A mix of potting mix, compost, straw, or hay should provide the right amount of organic matter while also providing sufficient drainage.
When planting in the garden, dig a v-shaped trench about 6 inches wide and 8 inches deep. Taper the bottom to about 3 inches wide. Spread and mix in aged manure, compost, and/or leaves.
In each trench, place a seed potato every 12 to 14 inches and cover with 3 to 4 inches of soil.
In 12 to 16 days after planting, when sprouts appear, use a hoe to gently fill in the trench with another 3 to 4 inches of soil, leaving a few inches of the plants exposed. Repeat as they grow (in several weeks), until the trench is at ground level.
When planting in containers, fill the container 1/3 to 1/2 full and plant seed potatoes.
In 12 to 16 days as the plants grow out, add more soil mixture, leaving 2-3 inches of leaves above the soil. Continue adding soil as the plants grow until you reach the top of the container.
Potatoes need at least 6 hours of full sunlight per day.
Maintain even moisture, especially from the time after the flowers bloom. Potatoes need 1 to 2 inches of water a week. Too much water right after planting and not enough as the potatoes begin to form can cause them to become misshapen. Stop watering when the foliage begins to turn yellow and die off.
Keep plants well weeded, especially when small. Weeds compete with crops for light, nutrients, and water, and can harbor insects and diseases.
Potatoes should have soil hilled around them a few times during the growing season to maximize your harvest. When soil is mounded, or hilled, on the plant stems, it encourages new roots to sprout from the buried stem, and more potatoes will develop on those roots. Hilling also preserves the harvest because if/when potato tubers are exposed to light for long periods of time, they produce chlorophyll and other substances that make them bitter. At least one of these substances, solanine, is toxic to humans in large amounts.
Hilling process: As plants grow, mound soil and/or compost around them a few times during the growing season until you have hilled about 12″ of soil around plants. It is a good idea to also mulch the hills to reduce weeds, retain moisture, and help prevent pests (see Pest Control). Alternatively, some gardeners plant potatoes in a barrel, grow bag, or similar structure, and add soil and/or compost as plants grow. To harvest, the structure can be opened or tipped over, exposing the potatoes.
Use a flat-tine digging fork or shovel, digging widely around the hill to avoid damaging the potatoes. Potatoes may be harvested in stages for a longer harvest period.
If you grew potatoes in a container, you can tip the container over onto a tarp, empty out the potatoes, and grow medium, making for easy harvesting.
Fresh, new potatoes
Harvest may begin any time after plants have begun to flower. Potatoes harvested at this stage should be enjoyed as soon as possible, as their soft skins don’t allow for long-term storage.
Once the foliage has died back or is removed, potato skins toughen which protects them from drying out, extending their storage life. Harvest 2 to 3 weeks after the foliage has died back. If your season is short and foliage has not died back, you can cut the plants down at the soil level three weeks prior to harvesting.
Curing Storage Potatoes: Unwashed potatoes should be cured in a dry, well-ventilated location for 2 to 3 days.
New potatoes or uncured potatoes should be stored for as little time as possible. Do not wash potatoes before storing, but you can gently knock soil off of them. Cured potatoes can be stored loosely packed (not in a sealed container) in a dark, cool (around 45°F), humid location for 2 to 3 months, checking tubers regularly and removing any that have declined.
Colorado Potato Beetle*
Use straw mulch to discourage the potato beetle, a devastating, pesticide-resistant insect. The mulch creates a habitat for predators of young beetles and makes travel difficult for the large, clumsy, adult beetles. Covering transplants with row cover is also helpful to exclude potato beetles and other pests.
*Despite the name, the Colorado potato beetle is widespread (entire US except AK, CA, HI, and NV) and one of the most difficult potato pests to deal with because it is pesticide resistant.