Broadleaf Root Dip

It is important to hydrate the powder to the right gel consistency, so that sufficient gel adheres to the roots to be effective but not so much as to be uneconomic.

The right consistency is when the powder has absorbed as much water as it can, with little or no surplus, unabsorbed water present. This is called equilibrium. The powder will absorb approximately 200 times its own weight of soft water and approximately 150 times its own weight of hard water.

Example:	Soft water	Hard water
100 grams of powder absorbs	20 litres (approx.)	15 litres (approx.)
1 Kg (1000 grams) of powder absorbs	200 litres (approx.)	150 litres (approx.)

1 Kg (1000 grams) of powder absorbs

A small experiment will determine the polymer-to-water ratio to achieve equilibrium. For example, add 1.5 litres of water to a suitable container and sprinkle 10 grams (about 2 teaspoonsful) of polymer powder into the container while agitating the water to prevent lumps from forming.

After about 3 or 4 minutes dip the bare roots of a plant into the gel. If the gel is too thick and too much adheres to the roots, add another 250 mls of water, stir, wait another 3 or 4 minutes and try again, adding more water if necessary until the desired consistency is achieved. If the gel consistency is too thin for adequate root-adherence, add more powder and mix, waiting 3 or 4 minutes before testing again. Then use the same final test ratio, e.g. 1 Kg to 150 litres for the full scale dipping operation. Suitable vessels for making-up the gel would be a bucket for 15 – 20 litres or a water butt or tank for 150 – 200 litres.

Where large numbers of stock are to be treated, this can be accomplished much more quickly by spraying the gel onto the bare roots. Place the pre-hydrated gel into a sprayer of appropriate size, according to the quantity of stock to be treated and with a spray nozzle suitable to allow the gel to flow freely. Set out the stock with the roots readily visible, on racking or layered on the ground. Ensure that the gel is of a consistency that will permit adequate flow, coverage and penetration amongst the roots. To achieve this, it may be necessary to dilute the consistency more than would be suitable for the conventional dipping method of treatment.

• Bare-root transplants can be treated singly or in bundles with equal benefit but ensure the gel penetrates fully amongst the roots of bundled plants.
• The ideal time for treating is as soon after lifting as possible.
• Gel spills should be cleaned up as soon as possible to remove a slippery hazard.

Broadleaf Root Dip