When to plant melons in Friday Harbor and the San Juans, WA

Heat is everything

Melons come from hot climates, and their seeds rot rather than sprout in cold soil. Growth crawls whenever nights drop into the 50s, which is normal for June west of the Cascades. That's why black plastic mulch matters so much here: it warms the soil several degrees and keeps it warm overnight. Lay it a week or two before planting, then cover the plants with floating row cover.

Melon roots resent being disturbed, so if you start seeds indoors, use individual pots and transplant them young, before they get root-bound.

Flowers, bees and sweetness

Melons make male flowers first and female flowers, the ones with a tiny melon at the base, a week or so later. Bees have to carry pollen between them, so take the row cover off once female flowers open. Poorly pollinated fruit tends to be small or misshapen.

Sugar is made in the leaves, so healthy foliage means sweet fruit. Water deeply while vines grow and fruit swells, then ease off as melons near ripeness. Heavy watering at the end dilutes flavor and can split the fruit.

East vs west of the Cascades

Eastern valleys like the Yakima and Walla Walla areas have long, hot summers, and melons grow there with little fuss, including larger, longer-season varieties. West of the mountains, pick short-season varieties such as Sugar Baby, Minnesota Midget or Halona, and use every warming trick: the sunniest spot, black plastic, row cover, and a south-facing wall if you have one. Limit each vine to a few fruits so they ripen before cool September nights slow everything down.