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Gibberellic Acid

January 24th, 2008, 07:04 PM
Has anyone used Gibberellic Acid? This is found in a product usually called Tomato or Pepper set.

Been trying to locate an online ordering source (in Canada - don't want to bother with cross border shipping).

Any help is welcome locating this to buy online, as it's not available locally. And since this is a small town, the people have small town brains and don't wish to special order stuff.

Would rather prefer the actual product of Tomato Set, but I do already have a source for pure Gibberellic Acid as a last resort, but it requires dissolving in rubbing alcohol first, then diluting with water.

Here's some info on it if anyone is curious as to what it does to plants.

The active ingredient is the man-made auxin (hormone) 4-Chlorophenoxyacetic acid (4-CPA) that is well known to promote fruit set commercially. Bio101--Why it works:

"...Fertilization within the ovules stimulates the ovary enclosing them to begin growing into a fruit. Within a few days the ovary begins to swell. This is called the fruit set.

Fruit development is under the influence of the plant hormones auxin and gibberellin. Pollen is one of the richest natural sources of auxin, so it is thought that the initial stimulus to fruit growth comes simply from the auxin to which the pistil is exposed as a result of pollination.

Applying the hormone auxin or gibberellin to the ovaries of flowers can induce a fruit to develop without pollination or fertilization. This is called a parthenocarpic fruit and is, of course, seedless."

Gibberellic acid was first discovered in Japan in 1935 as a result of the study of a condition common in rice plants called "foolish seedling" disease, which caused the plants to grow much taller than normal. The effects of gibberellins weren't widely understood until years later. Gibberellic acid, GA3 is a naturally occurring plant hormone that regulates the growth of plants, including triggering seed germination. Gibberellic Acid is not manufactured; it's a natural product extracted from the Gibberella fujikuroi fungus. There are over 100 known forms of gibberellic acid; GA3 is the most effective.

Seeds of many plant species require exposure to low or high temperature within a certain period before they will germinate. This process is called thermal stratification. Alternatively, the hormone gibberelline can be used to break such dormancy.

Alcohol soluble GA3 Powder 90% is the most economical form of Gibberellic acid. It is soluble in 70% common rubbing alcohol. Before it can be used is must be turned into a liquid. The amount of Gibberellic acid that needs to be used is very small. Drop the correct amount of powder in a small bottle, then add a few drops of rubbing alcohol. The only reason to use alcohol is to dilute the Gibberellic acid powder. Use just enough alcohol to wet the gibberellic acid powder. If after a couple of minutes you can still see some powder add a few more drops of alcohol. Then just add water to get he right concentration. It is often being said that alcohol will damage plants. Yes, but not in the very low concentration needed to dissolve Gibberellic acid. 90% GA3 powder will not dissolve in water. Once mixed it loses viability within a week, even if refrigerated.

You don't need much of the solution to soak your seeds, just enough for the seeds to fully swell. Most seeds can be soaked in the small poly-bags. Tiny seeds should be folded up in a filter paper for ease of handling when soaking. Larger seeds can be soaked in a pill bottle or small jar.

To know the concentration, replace X and Y, (X mg / Yml) x 1000 = Z ppm
To know the amount of solution to make to get a certain ppm, replace X and Z, (X mg / Z ppm) x 1000 = Y ml
To know the quantity of powder to use, replace Z and Y, (Z ppm x Y ml) / 1000 = X mg

For exemple: 100mg of GA3 in 200ml of water gives you 200ml at 500 ppm (part per million). 100mg of GA3 in 400ml of water gives you 400ml at 250 ppm. 1g of GA3 at 90% concentration will be supplied as a powder in a small ziplock bag, sufficient quantity to make a 2 liters of solution at 500 ppm. You should have enough for a couple of years.

Use strong solution, 500 ppm, on very hard to germinate seeds; and a 250 ppm on seeds that are just hard or slow to start. Seeds enclosed in a hard coat may be submit to a higher concentration, 750-1000 ppm. You can scarify the seeds at first. Soak seeds for 24 hours and at most three days for the ones enclosed in a hard coat. Keep the seeds at room temperature with occasional careful shaking. The seeds may then be sown. Don't use it on easy to start seeds unless you dilute it greatly, like 25-100 ppm, and soak them only for 2-3 hours. Normal, easy-to-sprout seeds will become very elongated and stretched out, then die if GA3 is used on them. Concentrations of about 2 ppm can cause tubers to sprout earlier.

Gibberellic acid can also influence the timing of flowering, flower gender, flower size and increase the number of flowers. If a plant is sufficiently developed, premature flowering may be induced by direct application of GA3 to young plants. Formation of male flowers is generally promoted by concentrations of 10 to 200 ppm, female flowers by concentrations of 200 to 300 ppm. You may have an increase in the number of flowers by direct application of GA3 to young plants, at 25 ppm.

When there is difficulty with fruit set because of incomplete pollination, GA3 may be effectively used to increase fruit set. The resulting fruit maybe partially or entirely seedless.

GA3 applied near the terminal bud of trees may increase the rate of growth by stimulating more or less constant growth during the season. Since GA3 regulates growth, applications of very low concentrations can have a profound effect while too much will have the opposite effect.