If you started plants from seed, the seedlings often come up crowded and need to be “pricked out”—separated from the other little seedlings and transplanted into individual containers. Here’s how to transplant pot- or tray-raised seedlings. Don’t worry. It’s easier than you think.
Why do we do it? We transplant young seedlings to individual containers in order to double or triple our supply of plants.
Trays of seedlings can be ‘pricked out’ (teased apart and transferred into their own plugs or pots) as soon as they’re large enough to handle. Most vegetable and herb seedlings are easy to prick out as long as you do it while they are young and have fewer than 5 leaves.
- Before you start pricking out, water the seedings (about several hours prior).
- Prepare the potting soil. Place as much potting soil as you need in a pail, and lightly moisten it with warm water. If the soil is cold from sitting outside, bring it indoors and give it time to come to room temperature.
- Prepare containers. Wash out plastic pots that have previously been used. Many sources recommend disinfecting containers at this point, but I think washing them with warm, soapy water is sufficient. When using paper cups or recycled containers like yogurt cups, poke at least 3 drainage holes in the bottom of each one.
- Label containers. Part of the beauty of paper cups is that you can write on them using a permanent marker. On the other hand, plastic markers can move to the garden with the plant, which makes it easy to tell one variety from another. I make markers from plastic food containers taken out of the recycling bin, cut into narrow 3-inch strips.
Partially fill containers with potting soil. Sprinkle enough moistened potting soil into the containers to fill them about one-half full.
Make holes in the potting mix with your finger or a pencil.
Remove the seedlings. Work with small batches of seedlings at a time so their roots don’t dry out. Ease the seedlings out of the tray they were growing in then carefully separate them, retaining as much potting mix around the roots as possible.
Push up on the bottom of the seedling container, and be ready to catch the root ball with your other hand. This is easiest if you can hold the container sideways or upside-down. Place the seedlings on a flat surface that is shaded from direct sun. Poke at the roots until the root ball shatters.
Replant the seedlings. Lift each seedling carefully by a leaf (never the main stem) and gently feed the roots into the hole. Use a stick or pencil to help guide the lowest roots into the new container, but don’t worry if they spiral around a bit. Still holding the seedling with one hand, sprinkle moist potting soil around the roots until the proper planting depth is achieved.
Firm the seedling in. If the seedlings are looking a little stretched it’s OK to bury some of the stem to help to support them.
Stop every ten minutes or so, and water the seedlings you have pricked out. Then return them to exactly the same environment in which they were growing during the previous week. To give new roots time to grow, wait at least three days before moving the pricked-out seedlings to brighter light.
Tips for Growing Seedlings On
Trays with smaller plugs are well-suited to most salad crops, especially if they will be transplanted within a few weeks of sowing. Use trays with larger plugs for bigger, hungrier seedlings such as cabbages, or for vegetables like onions that will be grown on to a large size before planting.
Prick out larger seedlings, or those of tender crops like tomato or pepper that won’t be planted out until after the last frost, into individual pots. They may need to be potted on once again before being transplanted into their final growing positions.
Keep potting mix moist but not too wet. Ventilate greenhouses, tunnels and cold frames on days when the weather is mild to reduce the risk of disease and molds.
Once the soil warms up to around 50ºF and has dried out a little, cool-season crops like lettuce, onions, beets or peas can be transplanted outside. Our Garden Planner can help you work out when is the best time to transplant your crops outdoors. Check out the green bars in your Plant List for a range of recommended dates for your location.
Hardening Off and Transplanting
Harden off (acclimatize) plants before transplanting by placing them in a sheltered spot outside during the day for a short time, and gradually extend the amount of time that plants are outside over the span of a week or two.
Plant seedlings into soil that has been enriched with well-rotted organic matter such as compost. Use a hand trowel, a dibber, or just your fingers to make holes in the soil. Place each seedling in its hole then firm in around the rootball and water to settle the soil around the roots.
Help new transplants along early in the season using row cover fabric to trap warmth and shield seedlings from the wind, cold and birds. Weigh down the edges of the fabric to prevent the wind from lifting the cover off. Remove covers once the weather has warmed up a little more. You may need to use beer traps to avoid problems with slugs and snails.
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