When to Plant Melons in Northern California

Timing for Starting Seeds Indoors

• Melons are intolerant of root disturbance so, although it is possible to start the seeds inside, you may lose the seedlings when you plant them out. Growing the seeds in peat pots helps because you can plant the entire pot and thus lessen the stress on the young roots. Wait until the end of April to start the seeds. This gives them time to develop strong roots before they are transplanted. When the plants have three sets of mature leaves, get them into the garden.

Timing for Direct Seeding

• The optimum air temperature range for melon seed germination is between 70 and 90 degrees Fahrenheit. That said, as long as the soil temperature is warmer than 65 degrees, the seeds will germinate. To determine if the soil is warm enough to plant, insert a soil thermometer, 6 inches deep, into the soil in several places in the planting area and take an average of the readings.

Raised Beds to Speed Up the Timing

• It’s important not to plant the seeds too early because cold soil leads to root diseases. Since many northern California gardeners have a short melon season, it’s smart to get as much of a jump start on planting as possible. Growing the melons in raised beds may help because the soil in them tends to warm faster than garden beds. You might also consider planting the melon seeds near a south-facing building or wall that will radiate heat to the soil. Pat Munts, of the Spokesman-Review, also suggests watching the garden for where the first spring weeds appear. They typically sprout in warmer patches of soil.

Pre-Warm the Soil to Plant Earlier

• Gardeners in regions with much colder weather than northern California’s have some tricks to share. One of these is that covering the soil with plastic helps the sun, no matter how feeble its rays, warm the soil. The biggest debate over this method is whether to use clear or black plastic. Clear plastic warms the soil faster but doesn’t block weed growth, while black plastic warms the soil slower but prohibits weed growth. Whichever method you choose, moisten the soil in the winter before placing the plastic sheeting on the soil and anchor the material along the edges with bricks or rocks. Allow it to remain in place for six weeks.