Good Start for Seedlings

Transplanting seedlings can be a bit of a shock for young plants, but you can ease the transition to your garden by keeping them outside, but in their pots for a few days. This hardening-off process will help the seedlings adjust to brighter outdoor light, stronger wind, and temperature fluctuations while they are still comfortable in their pots. This is especially important if you raised your seedlings indoors, or just purchased them at a plant sale.
When your seedlings are transplanted, they begin new growth on roots, stems and leaves. This takes away some energy from the plant in adjusting to the new environment. By keeping your plants in the pots, but slowly exposing them to new growing conditions, you can ease the transition and prevent your seedlings from getting sunburned, broken in the wind, or shocked in the cold.
  • Light: Your garden gets much brighter light than seedlings on a plant rack at a garden center or a sunny windowsill, or even grow lights indoors. Planting in the ground before the plants have had time to adjust can lead to sunburn on the leaves, which turns them white in irregular patterns. Start by placing in a semi-shaded spot for a few hours, gradually moving the plants to full sun for the entire day. This process should be spread out over at least a few days.

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  • Wind: They also need to adjust to strong wind, especially the kind of wind we get in Chicagoland in the spring. They do not get that wind indoors or on a protected rack, resulting in thin stems that may break in a strong gust when outside. A few days with their stems swaying in the breeze, while still in their pots will help them get thicker and sturdier in time for planting. When planting your tender seedlings outdoors, be sure to pack in the soil around the plant so it is firmly in the ground.

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  • Temperature: Right now, our days are warming up but we still have cooler nights. Keep an eye on the weather, and if the temperatures drop below 50 for warm-weather crops like basil, tomatoes, and peppers, bring them indoors or protect with row cover for the night. If the temperature drops below 40 for all other plants, bring them indoors or protect as well.
With these tips, you can help your plants avoid “transplanting shock” and start growing as soon as they are in the ground, rather than repairing damage from sunburn, strong wind or cold temperatures.
If you’ve already planted your seedlings, or don’t have a place or time to harden them off, you can go ahead and transplant them. However, keep in mind that the plants are adjusting to a new environment and what they need most is water. Keep your seedlings well-watered for the first 2-3 weeks as they get established. This may mean watering daily, or applying a light layer of mulch to keep moisture in the soil.
By Breanne Heath