We appreciate hearing from anyone who has a problem with their garden, but early in the season we know that when “my peas and lettuce are up fine, but the cucumber seeds must be bad because they didn’t germinate,” it’s a good indication that the outdoor night garden temperatures are simply too cool for the heat loving seeds like cucumbers.
Especially this past cool, moist May in Colorado, avid gardeners must be strong and resist the temptation to sow seeds of heat loving varieties of seeds into your garden until the soil has warmed up and spring weather conditions have warmed and settled with outdoor night temperatures consistently in the 50-55° F (10-13° C) range. In our area that will probably be sometime next week.
Be confident that seeds planted directly into the garden when conditions are warm enough will catch up and surpass stressed seedlings that were planted too early. Don’t be fooled by a long warm weekend – wait until the weather has truly warmed up for several days in a row.
When temperatures are warm enough, seeds will germinate quickly and won’t languish or risk rotting in the soil waiting to emerge. Fast growing plants that don’t get set back by cold weather are less likely have disease problems and will grow past insect or bird damage much easier than seedlings stunted by difficult beginnings.
This includes sowing seeds for summer flower favorites like zinnias, sunflowers, morning glories marigolds, nasturtiams and cosmos. It’s best to direct sow your favorite heat loving herbs like basils, parsley, oregano and thyme, and all the many fruiting summer vegetables including cucumbers, pole and bush beans, summer and winter squashes, corn, melons, wqtermelons, and pumpkins.
tomatoes and peppers that won’t have enough time to mature to fruit unless started indoors.