Transplanting seedlings is labor intensive so it is best done as a group activity. Clean and sterilize the greenhouse and equipment before transplanting begins.. Assuming 15 volunteers with a couple of team leads supervising the work session, transplanting 6000 seedlings requires approximately six 1 ½ hour work sessions.
Transplanting Seedlings Supplies
Fill the six packs with potting soil and dampen the soil before volunteers arrive. Prepare labels to identify the plant variety and stick the labels on the end of each sheet of six-packs (there are 6 six-packs per sheet for a total of 36 cells per sheet). It is not necessary to label individual six-packs unless the sheet of six-packs contains a mixture of seed varieties.
To label the pots, I recommend using Avery 5520 waterproof labels. These labels can be printed on a computer, they are durable and they are easier to remove from the pots than paper labels.
Seed2Need has tried several ways to transplant seedlings.
- Prior to 2020, 7th grade students from Bosque School transplanted our seedlings as part of a service/learning program on hunger and poverty in New Mexico. 15 students were included in each transplanting session and their teacher, a couple of parents and 2-3 Seed2Need volunteers provided supervision. It took 15 students five 1½ hour work sessions to transplant approximately 6,000 chile and tomato seedlings for the 2019 Seed2Need gardens. The students did a great job and transplanting went well. However in 2020, Covid became an issue. When the schools were closed so we had to come up with another alternative.
- In 2020, we asked Seed2Need volunteers to transplant the seedlings. We set up a table in a driveway stocked with seedlings, potting soil and trays of pots. Volunteers did a drive-by to pick up supplies and they did the transplanting at home. For the most part, this worked well. However, there were a few scattered problems, i.e. a number of seedlings were scorched by the sun as a result of the transplanting being done outside.
- In 2021, Seed2Need volunteers transplanted seedlings on a patio. Although there were umbrellas providing shade, there was still too much sun and many of the seedlings were scorched.
- In 2022, we transplanted seedlings inside the Seed2Need greenhouse. The greenhouse was cleaned and sterilized before transplanting began to reduce the risk of fungus and the evaporative cooling system controlled the temperature. I believe this is the most comfortable and effective way to transplant seedlings.
For transplanting, you need potting soil that drains well to reduce the risk of overwatering. Seed2Need buys potting soil by the bale from Greenhouse and Garden Supply.
Once the seedlings have 2 sets of true leaves, you are ready to transplant them into larger pots (It takes approximately 4 weeks between the time we plant the seed and the time we transplant the seedlings). Based on past history, we estimate that on average 20 of the 25 seeds will sprout depending on room temperature, distance between the seed and grow lights, natural sunshine in the room, etc. Most will have their 1st or 2nd sets of true leaves by the time they are transplanted. Other seedlings may still have the seed sitting on top of the sprout and have no true leaves. Plant both types. By the time the seedlings are moved into the cold frame, both types should have leaves.
- Prepare the 6 packs for planting. The potting soil should be moist enough so a hole poked in the middle of each cell holds its shape. Sprinkle the soil with additional water as necessary. With your thumb, a dibble or a large ½” stick, poke a hole in the center of each cell.
- Remove the seedlings from the pot – Wind your fingers through the seedlings so the tips of your fingers support the soil. Turn the pot upside down to remove the seedlings and soil. Gently massage the soil or use a wooden skewer to loosen the soil until it crumbles and breaks apart easily.
- Pick up each seedling by a leaf (not by the stem), plant each seedling in a hole and press soil firmly around the stem and roots. Make sure that none of the fine, white roots are left exposed.
- Lightly water the seedlings after they are transplanted.
The transplanted seedlings should remain in the greenhouse for approximately 2-3 weeks. By then, the plants should be 6-8” tall. Two weeks before planting, move the plants into the cold frame to harden the plants.
Seed2Need uses a cold frame built out of straw bales and covered with row cover and shade cloth). The row cover protects tomato plants from beet leaf hoppers. The shade cloth helps prevent sun damage. Over a period of 1-2 weeks, harden the plants by exposing them to longer periods of direct sun every few days.
Protect Your Seedlings
At the time of the year when seedlings are moved into the greenhouse, the weather tends to be volatile. There are often nights (and sometimes days) when the temperature falls below freezing. If the temperature may fall below freezing, move two electric heaters inside the greenhouse, turn them on in the evening and turn them off when the temperature gets above freezing the next day. To conserve heat, close and lock the windows on the back of the greenhouse at night and reopen them the following morning. Reopen these back windows before the temperature gets above the maximum temperature setting on the Phason control unit so it does not put a strain on the fans and the evaporative cooling system.
In the moist atmosphere of a greenhouse, fungus can be a problem. Monitor the plants for fungus and spray the plants with fungicide as necessary. Contact Judy Jacobs if you need advise on what and when to spray. What looks like fungus could easily be something else.
Seedlings must be lightly watered every day. Be careful not to over-water the plants.
When a paper label gets wet, the paper deteriorates but the adhesive remains on the pot and it is time consuming to remove that adhesive. Waterproof labels are easier to remove. In most cases, the label comes off in one piece.
Note: I suggest using Avery 5520 waterproof labels to label the pots. These labels can be printed on your computer.