[Vegetables and greenhouse](https://dunger.ua/en/blog/categories/vegetables-and-greenhouse) # When to sow cucumbers for transplanting Published 2026-11-09 Updated 2026-11-09 To read 7 min Work back from a warm planting bed. Choose a pot, harden off your cucumber seedlings and transplant them with their roots intact. Sow cucumber seeds indoors roughly 2-4 weeks before the likely planting date. Work back from when your bed will be warm enough, and allow time to harden the seedlings off. A compact plant with one or two true leaves is often ready for the move. Use individual pots so you can move the root ball intact. Young cucumber roots are easily disturbed. ## How to work out the sowing date Decide where the seedlings will go: an outdoor bed, a bed under a temporary cover or a greenhouse. Then estimate when the soil will be warm at the depth of the root ball and when you can protect the plants from frost. Count back a few weeks from that window and check the directions for the cultivar on the seed pack. If you are preparing more than one place, compare [planting dates for outdoor and greenhouse cucumbers](https://dunger.ua/en/blog/when-to-plant-cucumbers) before sowing both batches on the same day. Air in an unheated greenhouse can warm considerably in the afternoon while the ground is still cold in the morning. Check soil temperature over several days. If possible, see how cold the air gets near the seedlings at night as well. A raised bed next to a sheltered wall may be warmer than an exposed, windy plot. In Ukraine, use the forecast for your locality and the conditions in your own garden to make the decision. ### When spring weather is uncertain - Choose the earliest plausible planting date and a later date in case the ground stays cool. - Include hardening off in your plan. Avoid moving a seedling from the room straight into midday sun. - If the dates are far apart, sow a few pots on different days. Label each batch with the date and cultivar. - Keep some seed for direct sowing in a warm bed if conditions do not come together for transplanting. ### What a cucumber seedling ready to move looks like The two smooth leaves you see first are seed leaves. True leaves appear later and take on the shape you recognise on cucumber plants. A small plant with a sturdy stem and a root ball that holds together can be easier to move than a tall one with roots filling its pot. Age in days is useful for planning, but before planting look at the leaves, the stem and how well the roots hold the mix. If the oldest batch is getting tall and thin, look at the distance from the light and how closely the pots stand. Leaves should not be permanently shading one another. Avoid setting weakened seedlings into cold ground just to free up shelf space. Conditions may improve within a few days. Meanwhile, give the plants appropriate warmth, light and careful watering. ## How to sow cucumber seeds in individual pots Use clean containers with drainage holes and a loose seed-starting mix. Moisten the mix before sowing until it feels evenly damp without dripping when gently squeezed. Use the depth given for the seed. If you sow two seeds as a backup and both come up, snip the weaker seedling at the surface once you can see which is stronger. Pulling it out can disturb the seedling you want to keep. - Label the date and cultivar. If you are comparing seed from different packets, keep them in separate pots. - Keep the pots in a warm spot until seedlings appear. Check for moisture below the surface before adding water. - Give the new seedlings enough light as soon as they appear. If you used a cover to retain moisture, remove it once the seedlings emerge. - Water according to the mix and empty leftover water from the tray. Avoid leaving pots in standing water. If a seedling starts leaning and stretching, compare where its pot sits with the others. The light may be reaching one edge of the tray more strongly. Move or spread out the pots so all the seedlings have enough light. For help arranging the growing area, see how to [set up light and watering for indoor seedlings](https://dunger.ua/en/blog/growing-seedlings-at-home). If you use a grow light, keep a dark period at night and follow the fixture instructions to avoid overheating the plants. ### Water and nutrients in small containers A small pot can dry quickly in sun. Its surface does not always show how moist the mix is around the roots. Lift the pot and see if it feels appreciably lighter than it does just after watering. Water when the mix starts to dry and let the excess drain. If the stem darkens at soil level and the seedling collapses, separate it from healthy plants and check whether the mix has been staying wet. Read the mix label to see whether it already contains fertilizer. Seedlings in a fresh mix with fertilizer already added often get through the first part of growth without extra feeding. Once they have true leaves and are growing with good light and suitable warmth, consider whether the mix needs extra nutrition. Pale leaves in a cold, wet pot are a reason to check conditions before increasing the strength of any solution. ## How to harden off and transplant cucumber seedlings Start with short periods in a protected spot away from strong wind and direct midday sun. Gradually give the plants more time outside and more light. If cold weather returns or frost is forecast, move the pots back under protection. Hardening means gradual exposure to changes in light and air movement. Cold treatment can damage cucumbers and does not prepare them for a frosty bed. On planting day, prepare the holes. If the root balls are dry and crumbly, water them first. Support the root ball with your palm and gently squeeze the sides of a plastic pot. Avoid pulling the seedling by its stem or teasing apart the young roots. After planting, check that the soil meets the root ball and water drains into the bed. If wind protection is needed, arrange it so that you can still ventilate the plants. If the soil is still cold and the roots are already circling the container, consider how long the delay will be. In a long spell of poor weather, starting a younger batch can be more practical than keeping large seedlings where there is little room or light. Later, once the transplants establish and begin growing in the greenhouse bed, use feeding greenhouse cucumbers by growth stage to decide whether their needs have changed. ### Compare two batches next spring When planting, note which batch had sturdier stems, whether the root balls held together and how long the seedlings took to make new leaves in the bed. Compare the batches side by side if you want to judge the sowing date. Warmth and watering could explain the result if they are planted in different places. The start of new growth after transplanting tells you more than the height of the seedlings on planting day. Keep the notes for next spring. ### What to do if planting is delayed For a short delay, spread the pots out so leaves do not shade each other. Check moisture after moving them. A pot by a warm window can dry faster than one in the middle of a tray. If the plants need longer indoors and a root ball already holds together, you can slip it intact into a slightly larger pot where there is enough light and space. After planting, watch for a new leaf in the centre. Check moisture next to the root ball before watering again, especially if the ground is still cool. ## Root feeding for seedlings that need it  ### [COMPLEX FERTILIZER FOR HYDROPONICS AND SOIL](https://dunger.ua/en/mineral-fertilizers/small-packaging/for-garden-crops/17-complex-fertilizer-for-hydroponics-and-soil) This liquid concentrate has separate directions for root feeding and leaf sprays on seedlings. For actively growing seedlings in a mix that needs added nutrients, follow the root-feeding method for soil or potting mix. The bottle contains 0.5 L. Before buying, account for the nutrients already in the mix and the volume of solution your pots need. The root and spray rates are different. [Plan areas in My Garden](https://dunger.ua/en/my-garden) ## Questions about starting cucumber seeds indoors ### It is easy to avoid this by sowing in individual pots. Before planting outside, check that you can slide each seedling out with its root ball intact and without pulling the stem. ### ### ## Rate this article No ratings yet. Be the first! Rate this article ## Discussion(0) This discussion is shared across all article languages. Loading… Share this article ## Related Posts  [Vegetables and greenhouse](https://dunger.ua/en/blog/categories/vegetables-and-greenhouse) ### When to sow melon seeds directly outdoors Check when the soil is warm enough to direct-sow melons, how to choose an early cultivar and how to manage a cover after emergence. 2026-11-09 • 7  [Vegetables and greenhouse](https://dunger.ua/en/blog/categories/vegetables-and-greenhouse) ### How to feed overwintered bulb onions in spring Check how fall-planted onions resume growth, when spring fertilizer can help, and what to change when the bulbs begin to swell. 2026-11-09 • 7  [Vegetables and greenhouse](https://dunger.ua/en/blog/categories/vegetables-and-greenhouse) ### How far apart to plant tomatoes outdoors and in a greenhouse Choose spacing for bush and vining tomatoes, leave room for access and work out how many seedlings fit each row. 2026-11-09 • 7 Order & Inquiry ## Get in touch  Order mineral and organo-mineral fertilizers directly from the manufacturer. We will help you choose the right product for your garden, farm or landscape. 2 hours response time Free product advice Personal manager Easy to get in touch Step 1 of 425% ### Hello! Let's get acquainted and help you Tell us what you are interested in? Press Enter to continue By clicking the button, you agree to [privacy policy](https://dunger.ua/en/privacy)