The good news is that most plants will bounce back between 7-14 days if they're given proper care (which includes rehydration). If this isn't possible because major damage was done or little healthy root system exists then expect about 2 weeks until improvement can be seen.
If a plant is overwatered, it will likely develop yellow or brown limp, droopy leaves as opposed to dry, crispy leaves (which are a sign of too little water). Wilting leaves combined with wet soil usually mean that root rot has set in and the roots can no longer absorb water.
Signs of root rot are slow growth, mushy stems, and wilting, yellow, distorted leaves (especially when the plant has been well watered, as wilting leaves can also be a sign of a dry plant).
One of the quickest, first signs of overwatering your plants is to observe occurs at the tip of the leaf. If the tip of the leaf is turning brown this is a sign of overwatering. Too little water will result in your plant's leaves feeling dry and crispy to the touch while too much water results in soft and limp leaves.
To dry out soil quickly, you can apply hydrated lime to the soil, add compost and then turn the soil thoroughly to aerate it.
Using a hairdryer directly on the soil is an easy way of removing that excess moisture easily. However, there are some things to take into consideration when doing so. When directed at the soil the dryer will only remove the moisture from the surface having the rest of the soil wet.
To rehydrate a very dry plant, place the entire pot into a sink, bathtub, tray, or bucket of water. Soaking allows the soil to wick up water from the bottom via capillary action, like sucking through a straw. Allow plants to soak for 30 minutes or until the topsoil feels damp.
A wilted plant can recover in a few weeks with the right care and attention to address the root cause of wilting. It is worth noting, however, that not every wilted plant has the stored energy to make a full recovery, and some plants can take months to look as they did originally.
Leaves begin to wilt and turn yellow or fall off, growth slows, and blooming may be delayed. In the most extreme cases, when conditions are ideal for the fungus to spread quickly, plants can die within 10 days.
The symptoms of waterlogging are similar to symptoms of drought. If you have been watering your plant but it is wilting, drooping, yellowing, and has black or brown roots, the soil is likely waterlogged.
If the soil feels dry, it's time to water. In the spring and fall and in cooler climates, it might be sufficient to water container plants every two to three days. In the summer and in warm climates, container plants usually require daily watering, unless they are succulents or other drought-tolerant xeriscape plants.
Make sure soil in a new pot is damp already, and water again after transplanting. If you're moving to a new spot in the yard, fill the new hole 3/4 full with water before setting the plant in. Let the water soak in around the plant a bit, pack the soil in, and water again.
Water Only When Needed
Push it into the ground around your plants. You want the top 2 or 3 inches of the soil to be dry, and the soil below that to be moist.
Set the pot in a shallow container of water (if size allows), allowing the soil to slowly absorb the water. This technique is known as bottom watering. It may take an hour or more to thoroughly re-wet the soil. Be careful not to leave pots soaking in standing water continuously.
After a drought, it's much better for the soil to get a slow and steady rainfall than a heavy amount of rain in a short amount of time. When the soil is too dry, it cannot absorb water in a quick amount of time, which can lead to flooding.
As for the leaves that still have brown tips, you can snip the dead parts away with a pair of scissors without hurting the plant. For some plants that have long, strap-like foliage, such as dracaena or spider plant, make your cuts at an angle to imitate the natural shape of the leaves.
The brown leaf tips will not turn back to green but you can trim the brown edges to get the plant back to looking healthy. Find out more here. If your are noticing brown patches all over the leaves, this could also be a sign of overwatering.
Plants naturally use and lose water through their tissues each day. Leaf tips turn brown when that lost water can't be replaced for some reason. Ideally, water flows from plant roots through stems and waterways until it finally reaches leaf tips last.