About half of the seedlings I start indoors grow exactly as
they should, with one sturdy plant near the middle of each seedling container, so that the root ball forms a plug plant type mass. The others come up crowded, and need to be 'pricked out' – gardening lingo for separating the little seedlings and transplanting them to individual containers. Gardeners who buy seedlings also do a fair amount of pricking out, because it’s not unusual to find several lettuce, basil or even tomato seedlings growing in the same pot. Transplanting the young seedlings to individual containers can double or triple your supply of plants.
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. Getting organized ahead of time is important, too, because once your hands are covered with soil, you don’t want to stop to make labels or find more containers. Using the following step-by-step procedure, I seldom lose a seedling.
- Prepare the patients. Pricking out is a form of surgery, so the seedlings should be in top condition. Water them several hours before you begin, and protect them from any type of stress.
- 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. Sprinkle enough moistened potting soil into the containers to fill them about one-half full.
- Remove the seedlings. 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. Grasp a leaf from the most accessible seedling, and gently lift it until it comes free. 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. Use a stick, pencil, or your fingers to firm the soil over the buried roots. Then do the same with the other seedlings.
- Water and wait. 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.
I often wait until I see signs of new growth to move seedlings outdoors to grow in brighter light, or to begin hardening off seedlings in preparation for setting them out in the garden. Most pricked-out seedlings recover from transplanting trauma in a few days, and show new growth within a week. Those that won’t go into the garden for several weeks will need to be shifted to larger pots, but "potting up" older seedlings with strong root systems is a piece of cake compared to the slow, delicate work of pricking out.
By Barbara Pleasant