In addition to ensuring your plant an adequate water supply, bottom watering may prevent, you may be able to ward off pests that are attracted to moist topsoil. Finally, when you water your plant from the bottom of its pot, you can encourage robust root growth.
This could lead to overwatering unless you leave the pot in the water for long enough. But then the soil might have a hard time draining, which can mean your plant is sitting in soggy soil for too long. Not good! With a well-draining pot and aerated soil, overwatering shouldn't be an issue when bottom watering.
The downside of bottom watering plants
In terms of plant health, there aren't a lot of drawbacks to watering plants from the bottom. However, one consideration would be that continual bottom watering could lead to a build up of minerals and excess salts in the growing medium, especially if you're using tap water.
That's not the case when bottom watering. All you need to do is set the potted plant (be sure it has drainage holes) into the bathtub, sink, or another container that's filled with a couple inches of water. After 15 to 20 minutes, the plant will have absorbed the exact amount it needs—never too little or too much.
However, bottom watering is a more controlled method of watering your plants. By remembering to check your plant every ten minutes or so while it's sitting in water, you can significantly reduce your chances of overwatering and causing root rot.
These plants are prime candidates for bottom watering: Plants with hairy or fuzzy leaves, such as African violets, or plants that don't like getting their leaves wet, such as snake plants, Philodendron verrucosum, and P. micans.
Bottom watering is okay for smaller 4–6-inch plants, but we don't recommend this for larger plants. The time it would take to soak the roots in a larger potted container and get the full capillary action to the top of the soil may be too long. Plus, it would take a larger bucket to do it in too!
When bottom watering potted plants, the key is in the timing. Push your finger into the soil between the wall of the container and the stem of the plant. If you push down to the second knuckle and still don't feel moist soil, it's time to water the plant.
Bottom watering has advantages such as preventing mineral deposits on leaves and reducing the risk of fungal diseases. Additionally, it promotes healthy root growth by encouraging roots to reach deeper into the soil.
It depends on the size of the pot, type of pot (plastic or clay), how dry the soil is, the type of potting medium, and the density of the root ball. Larger plants might need a few hours, whereas small plants in smaller pots will take considerably less time. Some people even bottom water their plants overnight.
Some plants won't respond well to this method if they have sensitive roots and can't tolerate higher levels of salt and mineral buildup. This is the main issue with bottom watering, as the soil doesn't have a way to dispose of these materials.
Bottom watering doesn't flood the soil surface, so the topsoil tends to dry out faster using this method. It would be better not to allow water to penetrate all the way to the surface; but, even so, bottom watering will still help reduce your gnat population.
He recommends: 'Using a mixture of bottom watering for every day with top watering to wash away the build-up of salts and minerals will keep your plants healthy, strong and well-watered. ' The build-up of salts should be dealt with every couple of months by watering from above.
“Bottom-watering” is when you put your parched plant in a bucket of water and let it soak up what it needs through the drainage hole. (It's very fun. “Like a magic trick,” said Adams.) This keeps the top of your soil dry and therefore gnat-egg-proof.
If you don't have a drainage hole in your pot, you probably shouldn't use it for an outdoor plant, unless the plant will be sheltered from rain. You need to micromanage the amount of water going into your pot; if it get's drenched in a downpour, all could be lost. More soil means more moisture for longer.
High moisture levels in the soil can increase the risk of fungal, viral and bacterial infections in your plants. Overwatering might still happen in a pot with drainage holes, but the risk of over saturated soil is much lower.
Because the water isn't going top-down, it doesn't remove any salts from the soil. Bottom watering is more time-consuming—you have to check your plant, fill the tray, wait for it to absorb, and drain the excess as well. We'll be honest: for larger plants, this method can take quite a bit of time.
Bottom watering is the easiest way to rehydrate hydrophobic soil.
Gardening FAQ
The problem with your soil resisting hydration is not uncommon. It usually begins with the soil being watered incompletely and then drying more than it should. After that it can become hydrophobic and actually repel water! The ingredient in the soil that is causing that problem is peat.
If the soil is wet, it's overwatered - if it's dry, it's underwatered. Browning edges: Another symptom that can go both ways. Determine which by feeling the leaf showing browning: if it feels crispy and light, it is underwatered. If it feels soft and limp, it is overwatered.
Place the container in the water and let it sit for about 15 minutes so that the soil can soak up all the moisture it needs. Larger containers need to sit for a bit longer, and smaller containers for bit less time. Keep an eye on things. If the soil soaks up all of it during those 15 minutes, add more.
Stop Watering the Plant
But stopping your watering is always the first step. If you're overwatering, you'll likely notice that the soil is wet, so you want to make sure that soil is bone dry before you're ready to break out the watering can again.
Allowing the soil to dry out in between waterings (while not stressing the plant) is really important for preventing disease, mold, and growing stronger and healthier plants. Less frequent but deeper watering is better than frequent shallow waterings (once plants are established).