The Correct DWC Water Level Needed For Hydroponics

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By Jeff Hale

A DWC setup is one of the most effective and sort after types of hydroponics systems.

They allow you to grow plants in a non-soil environment with nutrient-rich water, and they’re relatively easy to set up.

When it comes time to add more water to your system, there is some confusion about how much you should be adding at a time.

Let’s talk about the correct DWC water level needed for your system so you can get back to growing plants like a hydro legend.

New to DWC? This Home starter kit is exactly what you need to start growing hydroponically with Deep Water Culture. It’s ideal for 6-11 plants and comes with everything you need to get going.

Also read: Best DWC Hydroponic System

What is the exact water level needed for DWC?

So the water level should be high enough to water the plant roots, but not too high that it causes oxygen depletion in your reservoir.

What is the exact water level needed for DWC?

The best way to check this is by using an EC (electrical conductivity) reader. This will give you a reading of how much nutrients are dissolved in the solution and can be used as a pretty quick guide for knowing if there’s enough nutrient flow through the system.

However, this is not an exact measurement of water level in your DWC reservoir, and you should still monitor the plant roots to ensure they’re submerged at all times.

Eye check: If you see bubbles coming from the bottom holes of your net pot where excess oxygen is escaping, then you know for sure, the water level is too high and needs to be lowered.

As well as that, it’s worth checking your air pump for minimum and maximum levels – if the plant roots are above this line in the DWC system, they will not get enough oxygenation from the airstone.

How To Setup a Hydroponic DWC Deep Water Culture System

How can the water level boost your plant’s growth?

Having the correct water level is vital for your plant’s survival. Many people struggle with their DWC hydroponics system because they do not understand the proper water level needed for hydroponics.

There are a few things you should consider when determining what an excellent deep water culture water level would be, such as:

  • The size of plant you’re growing – is it small or large?
  • Seedlings vs. mature plants – does it need a deeper water level for DWC hydroponics?
  • Container size – are you using one that is too shallow or deep?

The answers to these questions will help determine the DWC water level needed for your specific plant and system.

The correct topping up method to use for DWC systems

Your DWC water level will decline naturally over time because of the photosynthesis process, giving your plants a chance to grow. You will have to top up the water level with a nutrient solution when it is low.

Two main topping up methods can be used for deep water culture system: dripping and flooding. Regardless of the method you choose, DO NOT overfill or underfill – this can cause problems such as root rot which would kill your plants.

When you top up the water level, use a measuring jug to measure out how much nutrient solution is needed and pour it into the DWC system until just below the air stone.

Ensure there are no gaps in between each plant or other holes for this excess liquid to go through as it can cause plant root problems.

Why this method works

It allows you to top up the water level without needing to remove any plugs, tubing, or equipment in order to fit a container underneath – which could cause algae growth and bacteria build-up.

The nutrient solution will simply rise through each plant’s root zone when it’s dripping into the system.

Best Approach? If you want to increase your DWC water level quickly, as it will push out any excess liquid very fast – but this means that you have less control over how much nutrient solution goes into the tank and there could be gaps in between each plant for some of it to go through which can cause root problems.

The slowest method of topping up your DWC system, but you have more control over how much nutrient solution goes into the tank.

You will need to remove plugs, tubing, or equipment in order to fit a container underneath – which could cause algae growth and bacteria build-up.

How to prevent water evaporation

As photosynthesis does its thing, your water will be exposed to some light rays. This will result in some of the water evaporating.

When this happens, your plants will be left with insufficient amounts to keep them happy and healthy. If you want to avoid that happening, it is best to install a cover over your DWC system like an ebb-and-flow lid or some other type of cloche. These can help prevent evaporation.

Worried about overheating?

If you are worried about your air ump overheating, or if you have a small system that is not worth the expense of adding covers to, there are other ways around it.

You can place ‘evaporation control inserts’ into your DWC container until they reach water level. These will absorb some of the light rays and reduce evaporation.

Use a floating plant

Another option is to use a floating plant cover in your hydroponic reservoir. This will help control the humidity of the environment and reduce water loss through transpiration by plants’ leaves, which can lead to dehydration.

Change the hydroponic system reservoir

The absolute last-ditch solution (which you should only resort to if everything else fails) is to reduce the frequency of your reservoir changes. This helps to not lose too much water and can provide enough for your plants in between top-ups.

You should always aim to maintain a constant, stable level in order for optimal plant growth in DWC hydroponic systems.

What is the correct water level for a seedling in DWC?

You should aim for the water level to be between 12.95cm and 14.05 cm deep in your DWC bucket when you are using net pots for seedlings.

However, the best way is to place a ruler into the reservoir or use some kind of measuring device that can determine this measurement accurately.

How many gallons of water does a DWC plant need?

Smaller plants need less water, but larger plants need more.

Pro Tip: Use half a gallon (or liter) per plant for every week the crop is in veg and then one to two gallons (roughly four liters) when it’s in bloom.

So what do we mean by “half a gallon per plant”?

This is the water level at which you want it to be for most of your growth.

For example, if you have four plants in a DWC system then half of eight gallons (two liters) would be four gallons (15 liters).

Conclusion: DWC hydroponic system levels

Your DWC system shouldn’t be any higher than the bottom of the basket. At the most, maybe an inch beneath the small spot of air between the two.

If your plant’s roots don’t touch the very bottom of your basket, just bring the water level up slightly, to reach the roots.

Are those pesky roots poking out of the bottom and sides? Then drop the water, so it’s sitting below the basket.