How to Care for Cucumber Seedlings

You’ve given yourself a jump on the gardening season by starting your cucumbers indoors six weeks before your last frost date. Now, your seedlings have sprouted and their first, jagged-edged “true leaves” have emerged. In other words, it’s time to start a seedling care regimen that will turn them into vigorous fruit-bearing vines in just a couple of months.



While peat pots of seed-starter mix are great for germinating cucumbers, they have nothing to nourish the seedlings. To fix that, you need to move them — in their pots — to larger pots of organic potting mix. Your cukes will thank you because:

  • Keeping them in their existing peat pots during the move minimizes their risk of going into transplant shock.
  • Larger pots let them develop the larger root systems they’ll need to support their rapid growth.

Expert gardener’s tip: Choose containers about one-quarter to one-third larger than the current ones — for example, move a 3-inch to a 4-inch one.


Water the seedlings well. While they drain, fill the bottom quarter of the larger pots with the organic potting soil. Carefully peel away the top one-third and bottom of the seedling pots to expose the roots and then center them in the larger pots. Fill around them with more soil and water lightly to settle it.


Cuke seedlings need enough daily water to keep their soil moist. Water just enough that the peat pots neither wick away all the moisture nor begin disintegrating from it.


From the time they sprout, cukes seedlings need a daily minimum of six hours of light. If possible, place yours in a south-, southwest- or southeast-facing window. Weak, leggy seedlings are short on sun . Supplement whet they get with full-spectrum LED lights. Hang the lights at the manufacturer’s recommended distance from the plants and keep them on 24/7.

Expert gardener’s tip: Set your individual pots far enough apart that the seedlings won’t begin to shade each other as they grow.


As the descendants of plants originating in Southeast Asia, cucumber seedlings like it warm. Aim for a daytime temperature of around 74° F (23°C) with nights ranging between 60° and 70°F (15° and 21°C). To give the seedlings an edge on adjusting to outdoor life, place an oscillating fan nearby. The moving air will begin to windproof their stems.


Choose a warm, calm day one or two weeks before you intend to plant your seedlings in the garden. Set them in a sheltered spot with indirect sunlight for about an hour. Repeat each day, gradually moving them into direct sun. When they can tolerate it from morning until dusk, it’s transplanting time!.

Expert gardener’s tip: During the hardening-off process, skip any days when the temperature is forecast to drop below 60° F (15.5°C).