Rootbound plants

I’m growing 46 babies in two ebb and flow trays under 1,400 watts of HPS (a 1,000 and a 400) on a six by five-foot table with a six-foot light track in a typical “box” setup and an AC unit mounted on the side. The air is enriched with CO2 from a tank and regulator. The plants are between two and three feet tall and are three weeks into flowering but they are planted in five-inch round containers.
The roots are growing out of the containers and spilling out in the trays. I don’t have room for larger containers, but I could fill the trays with grow rocks. Unfortunately, this will not allow me to remove any of the babies until they are ready to be cut. They still look great but I’m worried they will become rootbound. What should I do?

B. Prid,

The plants will grow bigger buds if the roots are provided with more space to colonize. The roots are already growing out of the containers. By providing rooting medium for them you will allow them to develop in a healthful environment. If you could provide a two-inch layer under the containers as well as spreading the grow rocks around and between the containers the area will be increased considerably. Adjust the ebb and flow levels higher if using an underlayer of rocks.

One problem with using the ceramic pellets is that they are about the same weight as water and don’t stay firmly in position with high water levels. Other mediums such as red lava or pea-sized gravel can be used instead. They will hold in place.

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