Quick Guide to Bottom Feeding Coco

Conventionally the cannabis plant is always watered from the top, just like any other plant. But many growers have switched to bottom feeding coco substrates after several forum users started showcasing a few benefits to bottom feeding.

What is bottom feed coco?

Coco is a substrate that looks similar to soil. However, it is made from coconut husks and is therefor classed as a hydroponic setup. The ‘bottom feed’ refers to the water being placed in a tray underneath the plant, rather than the water being placed in the top of the plant pot. Once the water is in the tray the plants substrate must be in contact with the water – it will then begin to suck the water from the tray up into the pot.

Why is bottom feeding cannabis plants better?

There are a few reasons why many people believe that bottom feeding is advantageous to top feeding.

When watering from above, the coco is slightly compressed every time due to the weight of the water. This removes pockets of oxygen from the substrate. Roots love to have plenty of oxygen and when the medium is compressed there are less gaps for oxygen within.

Many people believe that when the water is bottom fed, the roots will grow faster downwards towards the water source, ensuring more root growth than when top fed. More roots equals more yield and improved plant health.

Roots, particularly new roots, are very fragile and can be damaged easily. If you dump 1 or 2 litres of water in the top of a plant pot in one go, the medium will move around a lot as the water passes through. When the medium is moving new roots can be damaged, broken or stressed. Bottom feeding is much more gentle on the roots as the medium slowly absorbs the water over time.

With regards to the benefit above, bottom feeding is much faster as it is harmless to dump 1 or 2 litres into the tray below as it will not damage anything. Where as if you need to feed the water from above, you would have to do it slowly over time.

Problems with bottom feeding

Whilst there are plenty of positives to this technique, over watering is one quite serious problem that a grower would need to watch out for. If too much water is placed in the below tray, the plant will absorb what it needs and leave the rest. If the plant is left submerged in water the roots will develop root rot quite quickly. Types of algae could also form in the excess water. This plant problem is easily fixed by watering the right amount and checking an hour or two later and removing any water left in the tray.

Another issue is that the plant will not get a natural flush from watering to help remove nutrient salts that build up (which could cause nutrient burn). When watering from above it helps to flush out any excess nutrients and salts, this is not always an issue but it depends on how much feed the grower is giving the plant. Once every 10 days a grower could top feed to help combat this issue.

How to Bottom Feed Cannabis Plants

Using fabric pots instead of plastic is very important as the whole pot will absorb the water from the tray far quicker than a plastic pot which will only absorb through the drainage holes.
A grower would not want to use clay pebbles at the bottom of the pot either as it will hinder the water uptake (some do this to increase airflow under the medium).

Conclusion

When you consider the above facts it seems obvious that bottom feeding has some pretty amazing advantages. There are only really two issues to look out for which are written above. Both issues are easily rectified so it does seem like bottom feeding is a solid technique that may become adopted more and more. It is very popular among Sea of Green growers where watering hundreds of tiny plants would of taken hours!