More on gibberellic acid
As mentioned, gibberellic acid (GA3) it is now available for purchase in portions of 1g.
I brought it in only in the idea of helping BotanyCa customers and it is available only coupled with purchases of seeds. It certainly makes no sense to use envelopes and have trips to the Post Office to ship only 1 g of GA3.
The gibberellic acid is a plant growth regulator with various applications; here we only discuss its usage for improving seeds germination. Keep in mind that it is not a ‘miracle treatment’ in regards to germination. But of course in some situations it provides good results and can be very useful for people who don’t benefit of a cold winter. In most of Canada we could actually get by germinating most species without using GA3.
The main usage of the GA3 in seeds treatment is to improve the germination for hard to germinate species, older seeds, and to speed up the germination for other species.
It usually replaces the seeds need of a cold/moist stratification period (but not always and not for all species).
It can also be used for species which have seeds with immature embryos (mainly Ranunculaceae); it has been found to promote embryo growth, so indirectly it will improve germination.
The GA3 provided has the aspect of a crystalline powder and is supposedly 90% pure.
Because I never used it in powder form, and I actually never had this type of GA3 90%, I decided to give it a try before sharing it, by using it both ways: as powder and solution.
I used Gentiana lutea 3 years old seeds and Aquilegia flabellata var. pumilla older seeds (both hard to germinate, especially if the seeds are not fresh).
Preparing a GA3 solution the easy way (you can use a plain sheet of paper and a regular small bottle; use the kitchen measuring cup for the water amount)
All the steps required to prepare a solution using high purity GA3 were described in a previous post. Following the method described to prepare a solution, I made 250 ml solution of ‘less than 1000 ppm’ (because the GA3 is only 90%). It is fine as we are not doing scientific experiments that require precision.
A picture is worth a thousand words so I illustrated in the plate how to prepare the solution without the need of a fine balance to weight the amount of GA3.
Many people are in the habit of employing the GA3 ‘as it is’ by sprinkling the powder over the seeds. On many websites you will find various options of this advice said to be taken after Prof. N. Deno.
“A 2.5″ square of paper towel is folded 3 times to give a pad .5″ x 1″. This is moistened with water and the seeds are placed on top. Over the seeds is sprinkled the amount of GA3 that can be balanced on the narrow end of a flat toothpick. The pad is then placed in a plastic baggie. After 24 hours the seeds can be sown in the normal fashion. This technique gives a concentration of 1000 ppm.”
My observations: at least for this type of GA3, it is impossible to use the ‘toothpick’ method, the crystals are too large to be ‘balanced’ on a toothpick. Use a sharp knife blade end or something similar. Also, by sprinkling some powder over the seeds and adding water, there is no way to know the concentration of the GA3 used!
Step-by-step treating seeds with GA3 in powder form and solution
After about 10 days, Gentiana lutea seeds germinated very well, even when using the GA3 powder. So, Gentiana lutea is back in stock, recommended to be paired up with GA3. Only a few of the Aquilegia seeds show slight signs of germination, but they are hard to capture with my camera for now.
Conclusions:
At least for Gentiana lutea, the germination percentage was better for the ‘solution treatment’ compared with the ‘powder treatment’. This is probably because by using the powder, the coverage of the seeds is not uniform. Sprinkling the powder also works, so it is anyone’s choice.
It is much easier to prepare a GA3 solution, keep it in the fridge, and then use it on seeds. On previous occasions I kept in the fridge and used the same solution GA3 for 2 years with good results. The powder will preserve its potency even longer (keep it labeled in the fridge).
You waste less GA3 by using a solution and have a relative control over the concentration used. You can treat a LOT of seeds with 1g of GA3!!! Most likely no one uses that much.
Keep in mind that after the treatment, the seeds may germinate fast, so do not start the GA3 treatment until somewhere in early to late spring, depending if you start seeds under lights indoors, or outdoors.
