My team and I have been asked a lot lately on whether they should aerate their water prior to feeding/watering their cannabis plants. After discussing with them and digging into some research, we found that it is situational but typically always beneficial to take the extra step. One thing we found with certainty is that it never hurts to do so, but we'll explain the science behind this technique and hopefully clarify whether or not this could be worth your efforts.
What Aerating Does
When you aerate via air pumps and air stones, it introduces dissolved oxygen to your water. This infusion of dissolved oxygen (DO for short) occurs in 2 different ways: through surface agitation and through mere contact with oxygen bubbles. This DO is then ready to be absorbed by your plants through the root zone.
Why Does Water Need Oxygen
Plants need oxygen to respirate. They absorb oxygen primarily through their roots, and partially through their stomata (pores on their leaves) and pores on their stems. If the water in a hydroponic setting is low on DO, the roots of the plant cannot convert their stored sugar into energy, and the plant will begin to die. Low DO in a hydro setting also leads to anaerobic bacteria and fungal build up (pythium aka root rot) which binds to the roots and further prevents them from absorbing vital resources.
Plants in a soil setting absorb oxygen through the air pockets present in the soil, as well as through the DO present in the water (in natural, rain water absorbs DO from contact with the atmosphere). When you over water, the plant is deprived of these air pockets and limited to the amount of DO present in the water you applied. When that DO runs out, the plant will begin to suffocate.
The Benefits of Aerating Water
When it comes to having DO in water, one rule of thumb is that you can never have TOO much oxygen. Like water, the plant will absorb what it needs and the excess oxygen will never become toxic.
Aerating your water can also assist in evaporating chlorine that is present in your tap water. This proves to be a much more cost effective means of filtering your water, all while infusing it with that precious oxygen your plants need. Be advised however, because there are a lot of towns that use a similar chemical called chloramine, which does not evaporate. It is always good to check your local water report to see what is in your tap water.
There are many benefits and little to no downsides (other than setup time) to aerating your water prior to watering your plants. The pumped air will increase DO levels in your water which benefits your plants' roots, and it can also decrease chlorine levels through increased surface agitation. Your plants can never receive too much oxygen, so if you have the time to let your water sit for a few hours while you let the air pump work its magic, this process can lead to plenty of benefits for your grow op.