Overwatering is a very troublesome problem. You need to combine many situations to judge whether your plants are overwatered. Today we would like to share with you how to water your plants perfectly, we will start with five aspects:
How to Water Plants Perfectly
This section breaks down good watering habits in a variety of different situations.
Seedlings
Don’t give more than 2-3 cups (500-750ml) of water at a time until plants are at least 2 weeks old. Typically seedlings need to be watered every 2-3 days. Every grow is a little different because plants drink more or less depending on how big they are, the environment (temperature/humidity/airflow), the grow medium, and the size/type of pots. However, most seedlings will do well with 2 cups (500ml) of water every 2 days for the first 2 weeks. However, this is a very general guideline. If the top of grow medium looks wet, wait an extra day or two to water. If the grow medium looks totally dry, either water more often or more at a time.
Big pot, small plant
Give just a little water at a time in a small circle around the base of the main stem. Once plants are bigger and drinking more, you can start fully watering them. The 2-2-2 rule from above should work for seedlings in a big pot (2 cups of water ever 2 days for the first 2 weeks after germination). After that, start giving a little more water at a time until you’re able to water plants thoroughly. We’ve found that plants often grow the fastest when you figure out the perfect amount of water that allows you to water every other day.
Not sure whether to water? Pick up plant pots
When a grow medium is soaked with water, it feels as heavy as a brick. However, when soil or coco is dry, it becomes almost feather-light. That means if you pick up your plant and it feels surprisingly heavy for its size, you should wait a bit longer before watering (and possibly give less water at a time for now). If you pick up a plant and it feels surprisingly light, that means you should water plants today!
Watch topsoil
If the topsoil looks wet all the time, you probably should be watering less. Especially if you’re seeing fungus gnats, green algae, or the top looks hardened with divots where water is getting poured too often.
What to do with a too-thick grow medium
If your grow medium is extremely thick or muddy, you have two choices. You can either ride it out and hope for the best, or transplant plants to a better grow medium. If your plant seems to be getting better as it gets bigger, or if you find a different watering schedule that seems to stop the symptoms, you can probably skip transplanting. It’s possible to stunt plants during transplanting so you don’t want to do it if you don’t have to. But if plants are growing poorly despite you altering the watering schedule, you may have to give roots a new home or the plant won’t ever thrive.
If your grow medium is too thick, you can either transplant to a new grow medium or try to let plants adapt. The worse the grow medium, the more you should consider transplanting.
How to Water in Super Soil
If you’re growing in super soil (composted, organically amended grow medium), you don’t need to add any nutrients from seed to harvest. This is super convenient, but you must ensure you aren’t accidentally washing away extra nutrients. In a super soil setup, you’re trying to conserve all the nutrients. The beneficial microorganisms in the soil work together with roots to make sure plant is getting the exact right amount of nutrients at the right time, just like in nature. That means in super soil, you should almost never water plants until they get runoff out the bottom. Whenever runoff water is coming out the bottom, it’s draining away nutrients with it. You’re basically looking to water plant just enough to saturate the medium but none comes out the bottom.
Growing in super soil lets you go from seed to weed without adding any nutrients, but you must avoid overwatering to prevent nutrient deficiencies down the road.
When to Start Watering to Runoff
If you’re giving plants extra nutrients in your water, you may want to give enough water to get runoff out the bottom. This helps prevent nutrient buildup in the soil. However, watering to runoff when plants are too small is an easy way to cause the symptoms of overwatering. So when should you start watering to runoff? This guide will help.
Plants are big enough to water to runoff when they’re about this size…
- 12″ (30cm) tall ~ 2-3 gallon container
- 24″ (60cm) tall ~ 3-5 gallon container
- 36″ (90cm) tall ~ 5-7 gallon container
- 48″ (120 cm) tall ~ 6-10 gallon container
- 60″ (150 cm) tall ~ 8-10+ gallon container
The type of plant container and grow medium make a difference, which is why the ranges overlap. A thicker grow medium needs to be watered less, while a well-draining or airy grow medium should be watered more. As far as plant pots, just remember that any container which lets air in from the sides (air pots, fabric pots, etc) need more water, more often. This is because water is constantly evaporating out the sides in addition to just being used up by the plant roots. In an air pot or fabric pot, start watering to runoff when plants are on the smaller side of the range. If your plants are in a hard-sided pot, wait until they’re a bit bigger to water to runoff.
What if my plant never gets that big? If your plants are in a big pot, or you’re growing very small plants, you may never need to water to runoff. In some cases, watering to runoff will cause the symptoms of overwatering even until harvest. In this situation, it’s up to you to watch the plant to ensure there’s no nutrient buildup in the grow medium.
When this happens, it kind of reminds us of growing in hydroponic setup because you’re basically treating the root ball like a nutrient reservoir.
How do you know whether to increase or decrease nutrient levels? If plants are getting dark green or showing nutrient burn, it means that you should lower the overall amount of nutrients in the water. If plants appear pale/lime green or lots of bottom leaves are yellowing and falling off, it means your plants want more nutrients overall. In that case, increase the overall nutrient levels in the water without changing the ratio.
How to water to runoff (Soil)
Once plants have reached a good size for their container, they’re ready to start getting watered with runoff. If you’re growing in soil, most plants have already used up the majority of nutrients by this point. That means if you haven’t been providing nutrients in the water yet, now is a great time to start.
- Wait until topsoil is dry up to first knuckle (alternative: wait until plant pot feels light to pick up)
- Water until you get about 10% extra runoff water out the bottom
- Remove runoff water
- Repeat
How to water to runoff (Coco)
In coco, you should be watering with nutrients from when plants are seedlings, so you never have to wonder when to start adding nutrients. However, coco-grown plants seem to want things to be just a bit wetter than soil-grown plants. Plants in coco don’t seem to react well to extensively drying out. That means you’ll typically end up watering a bit more often in coco than soil.
- Wait until top of coco appears mostly dry (with a few damp patches left) and pot doesn’t feel heavy
- Water until you get about 10% extra runoff water out the bottom
- Remove runoff water
- Repeat
You are now officially an expert on overwatering. You know all the crazy and surprising symptoms to look for when diagnosing your sick plant, and you also know how to water your plants perfectly every time. Congratulations!