Introduction
This note is not in reference to newer baby leaves. Sometimes leaves grow small and stay small as with the mint plants grown with starter aero garden. The featured image of this post is not yet accurate. This lesson was given for free courtesy of Swedish Plant guys on YouTube. Go check him out if his account is still active. Thanks Man!
Too much Salt
Over time, salt can accumulate in plants due to fertilizers used to ‘feed’ plants. Salts are highly soluble and can lock onto water particles which prevent the plant root systems from absorbing that water, this creates a situation where the plant cannot get enough water, resulting in smaller leaves. Symptoms include small white residue on the edges of the pot, or in the pot drainage area.
Remedy: The Answer to this is to flush the root system with fresh water. Verbatim says water the plant 4 to five times over the course of an hour allowing the drainage water to leave the system entirely. Or re planting the plant in newer, bigger pot with fresh soil, using as little of the old soil as possible. Should see the difference in a couple of weeks. I Noticed a similar phenomenon when the mints sprouted for the first time, it died and resurrected and looked as though it would die again, I flushed it with bottled water and it survived to its current state.
Low light
If smaller leaves present with the distance between the leaves gets longer and longer, this means the plant is not getting enough light. This is easiest to see with vine plants (like the mint).
Remedy: Give it more light to the plant. Re position the plant or adjust your lighting system!
Root Bound
The plant may have an extensive root system. The pot or the container is restricting further growth of the root system, it may also mean to much roots not enough substrate. Some plants like to be root bound, some don’t. Most tropical plants don’t like to be root bound.
Remedy: Re pot the plant or prune the root system, never cut away more than 30% of the root system.
Over watering
Overwatering the plant can result in what is referred to as “Root Rot” or other kinds of damage to the root system. Dysfunctional root systems can result in smaller leaves. Root rot can have be deep brown or black and carry a distinctive smell. Cut away the roots effected by the root rot and let the plant dry out in between waterings.