Painting DWC Buckets to lower water temperatures
When on the lookout for a DWC setup you will notice that nearly all of them are painted black. Whilst this looks nice to the eye, it is nearly always an issue for those who purchase one. The colour black absorbs more light than any other colour and this causes it to have a much higher surface temperature than materials painted in a different colour. The temperature of the water inside these buckets will then rise higher than if the bucket was painted white (which reflects light more than any other colour, leading to the lowest surface temperature).
One of the most common problems for a grower using DWC is the water temperature being too high. This causes a few problems such as algae and overall it leads to either a failed grow or a low-quality one.
What colour to paint a DWC setup
There is no doubt that the best colour to paint a DWC is white. This will reflect light, unlike black which simply absorbs it. With white paint, the water will easily drop a few celsius. For many growers, this saves the cost of purchasing a water chiller which is very expensive and loud.
How to Paint a DWC Hydro setup
It is important to use the correct paint which is made for plastic. Using a normal wall paint will start to crack and chip off quite quickly.
The new colour can either be applied with spray paint or a paintbrush. If using spray paint the whole setup needs to be taken outside due to the fumes being bad for both people and plants. If using a paintbrush the whole setup can remain connected which is much easier for most people.
If the DWC system has a shiny gloss finish some people like to use 240 grit sandpaper to lightly aggravate the plastic all over being painted. This helps the paint bond better and stops problems in the future.
If the system is not currently black then it is best to first put a coat of matt black paint on before the white. This saves doing multiple coats of white and provides a more solid finish.
Searching “paint for plastic” provides listings of websites that deliver along with local DIY stores where you can collect in person.
Here you can see the original colour was blue, so one coat of matt black is applied before the white.
Why are hydroponic systems finished in black rather than white
When plastic is finished with black paint it stops light penetration from passing through the buckets or trays and damaging the roots of the plant. This is why all hydroponic systems are supplied with a black finish. Painting them white on top of the black is the best solution as the light will still not pass through the original black paint, but the light energy will not be absorbed anymore by the black and transferred as heat into the water.
Instead of painting, some growers do prefer to buy a water chiller. However, these are loud and take up a lot of room. They also use more electricity so bills will be even higher. Painting the setup white is much cheaper and in some cases, it will bring the water temps down enough to get things working smoothly.
When a Deep Water Culture (DWC) setup is running smoothly the results blow classic methods such as soil out of the water. But getting a DWC setup running smoothly takes time, patience, and a bit of knowledge.