Potatoes are a staple crop most home gardeners associate with early spring planting, typically around the last expected frost date. This traditional timing allows tubers to develop fully during the long, cool growing season. If that initial window is missed, planting potatoes in early summer, specifically June, is frequently possible. Success hinges on selecting the right variety and modifying techniques to accommodate the summer heat and shortened season.
Feasibility of Planting Potatoes in June
Planting potatoes in June is often termed “second cropping” or “summer planting.” This late timing is most successful in regions with a long, mild autumn, which provides the necessary cool period for tuber bulking before the first hard frost. The primary limiting factor is not the summer heat itself, but the soil temperature, as tuber initiation is inhibited when soil temperatures rise above 75 to 80 degrees Fahrenheit.
The potato plant needs approximately 90 frost-free days to reach a harvestable size. Gardeners must count backward from their average first hard frost date to ensure the selected variety has adequate time to mature. Planting in June typically allows for a harvest in late September or October. While the overall yield may be slightly less than a traditional spring planting, the quality of the autumn-harvested potatoes can be excellent.
Selecting Quick-Maturing Varieties
A June planting necessitates choosing varieties with the shortest days to maturity to ensure development before the season ends. Gardeners should focus exclusively on “first early” types, which are generally ready for harvest within 75 to 90 days. Maincrop varieties, which require 110 to 135 days, should be avoided as they will likely be cut short by an early frost.
Selecting certified seed potatoes is important, as these are guaranteed to be disease-free and offer reliable, rapid sprouting necessary for a late start. Suitable varieties for this late planting window include ‘Red Norland,’ ‘Yukon Gold,’ and ‘Irish Cobbler.’ Some specialty suppliers also offer varieties specifically bred or cold-stored for second cropping, such as ‘Charlotte’ or ‘Maris Peer,’ which are excellent choices for a fall harvest.
Specific Planting Techniques for Late Season
Planting seed potatoes into warm June soil requires modifications to mitigate heat and conserve moisture. Since the ground is typically drier than in early spring, soil preparation for water retention is a priority. Incorporating well-rotted compost or organic matter helps the soil hold moisture around the developing tubers.
The planting depth should be slightly deeper than a spring planting, generally between five and seven inches, to position the seed potato in cooler, more consistent soil temperatures. After placing the seed pieces, which should each contain at least two eyes, the trench should be covered with only three or four inches of soil initially. Immediate application of a thick layer of organic mulch, such as straw or shredded leaves, is effective for shading the soil surface and preventing excessive warming that inhibits tuber formation.
Adjusting Care and Harvest Expectations
Consistent moisture is the most important factor once the June-planted potatoes begin to grow. During the summer, the plants require approximately one inch of water per week via rainfall or irrigation. Maintaining this consistent watering schedule is vital because moisture fluctuations can lead to misshapen or split tubers, particularly once the plants begin to flower.
Summer planting coincides with peak activity for pests, such as the Colorado potato beetle, and diseases like late blight, which thrive in warm, humid conditions. Gardeners must be vigilant in monitoring foliage and employing preventative measures like crop rotation. The harvest date is calculated by adding the variety’s days to maturity to the planting date, then confirming this against the average first frost date. These late-season potatoes are often harvested as smaller, thin-skinned “new potatoes,” offering a delicious, high-quality yield rather than a large, storage-grade crop.