Hydroculture Basics & The Importance Of A Water Level Indicator

The trick to keeping plants in Hydroculture is knowing your plants water requirements, your plants root depth and your reservoirs water level. The latter is easily measured with a Water Level Indicator. (These Indicators are fairly difficult to find, which is why I make my own or eyeball it. But they can be bought here.)

There are three zones to keep in mind when planting in hydroculture, 1) the dry zone, 2) the moist zone, 3) the wet zone.  Depending on the water requirement, it's important that the roots will end in one of the appropriate zones.  The majority of plants will be most comfortable with their roots in the moist zone.  The moist zone is determined by the absorption rate and retention of the soil less media.  Clay pebbles will retain water differently than for example vermiculite, perlite or rockwool. Below is a diagram showing the three zones.

Since the roots are suspended in the moist zone, they are not standing in water and receiving oxygen from the spaces between the soil less media.  This is why no bubbler or airstones are needed as seen in other hydroponic systems.  However, if plants of this nature are allowed to keep their roots in water (for an extended amount of time), they will most likely form root rot.  As a plant grows and root systems develop, their roots will grow into the wet zone.  At this point you might see signs of distress in the plant and just like with soil gardening, it will be time to repot to a larger container or alternatively, clip roots.

When repotting plants in hydroculture, it is important to know where the roots sit.  A common mistake is to over estimate the ability of the soil less media to create a moist zone, resulting in the plants root system being suspended in the dry zone or at least too much being suspended in the dry zone.  When using my home-made water level indicator, I place it slightly below the roots, not the bottom of the container. I know the bottom will have water, but I'm interested in keeping the water level slightly below the root system.

There are plants, however that are most comfortable with dry roots for an extended period of time. Succulents and Cacti come to mind.

Unlike the first example, where the plant can be watered solely by tapping of the nutrient reservoir back to a healthy level, the key with succulents and cacti is that they need to be watered from above. The water needs to pass through the soil less media, past the roots. The roots of succulents and cacti need to play just below and above the moist zone.  Bear in mind that I grossly generalized succulents and cacti, the most important thing to keep in mind that each plant has it's own comfort zones and part of the fun of hydroculture is to find that zone.

When I first stared gardening, I killed many plants by over watering. Even after I bought a self-watering planter, I was still killing plants.  And I almost started to with hydroculture, but my plants were quick to react to the right conditions, and I was quick to readjust my watering tactics.  Which was hard because I enjoy watering plants, except in hydroculture, you just don't need to water as frequently.

That being said, there are some plants that love to keep their feet wet, Hydrangeas and Louisiana Irises come to mind. Below is a diagram that shows an over watered plant in hydroculture or water-loving's plant ideal state.

As you start gardening in hydroculture, the fun will be in the experimentation of finding the right balance of water levels and nutrient supplies.  A lot of the guess work will be eliminated with the purchase of a Water Level Indicator and the room for error will be much smaller.  I highly recommend using one.