Why Plants Wilt
Reversing wilt begins with a basic understanding of what is going on in a plant when the leaves droop and the stems go limp. A plant wilts when the roots cannot provide adequate water to the leaves and stems. It seems counterintuitive, but both a lack of water in the soil surrounding the roots and an overabundance of water can cause a plant to wilt.
1. Dry Soil
Sink your finger into the potting soil around the wilted plants. If it feels dry one inch below the surface, lack of water is probably the cause of the wilt. Overly dry potting mix at planting time will pull any available moisture away from the plants' root zone, which could explain why your freshly potted plants would be wilting.
The Fix: Make sure to water in your plants right after potting them up, even if they were well watered before planting. In addition to preventing the surrounding potting mix from pulling moisture away from the root zone, this helps to settle the soil around roots so they can more easily access the water they need.
If the potting mix has dried out too much by the time you notice the wilting, it can be tough to hydrate it. Water poured onto the surface often runs right through rather than absorbing into the mix, where roots can find it. Instead, set the whole pot in a tub filled with several inches of water for 30 minutes. The mix will soak up water through the drainage holes in the bottom of the pot, slowly pulling moisture upward like a sponge.
2. Overwatering
Overly wet soil causes plants to wilt too. If the soil is saturated, roots can't get the air they need (yes, roots breathe) and begin to rot. With fewer functioning roots, the stems don't get enough water, and they wilt. Overwater a container garden for a few days—especially a container with no drainage holes in the bottom or blocked drainage holes—and it will wilt.
The Fix: If the potting mix is staying overly wet, check the container's drainage holes to ensure they are not clogged. Water should be able to escape from the pot easily. Do not place a container garden in a saucer, which acts as a water reservoir, keeping the soil constantly saturated.
After ensuring the pot can drain freely, give it time to release excess water. Do not water until the soil 1 to 2 inches below the surface is dry to the touch. Don't guess at the dryness of the soil when watering; always sink your finger into the soil to test the moisture level.
3. Transplant Stress
If the soil in the newly planted container garden appears to be moist, but not overly wet, transplant stress might be the reason your plants look wilted. The sometimes rough-and-tumble process of transplanting from one pot and growing location to another can cause some plants to wilt. Wilting is how some plants conserve energy while they acclimate to a new environment.
The Fix: The best thing you can do is watch and wait. In a few days, it's likely your newly potted plants will get comfortable in their new environment, and will perk up again on their own. Resist the urge to add more water if it's not needed.
If possible, keep the pot out of full sun, especially during hot weather. Warmer temperatures can cause young plants to lose water faster than they can take it up from the soil, which causes wilting. This problem lessens as more roots grow and the leaves thicken up a little more.
