Gentian seeds treated with GA3
by Herman Mylemans
I use the following method:
- Solution 500ppm, 20 mg GA3 (gibberellic acid-3) for 4 cl solution (distilled water)
- Put the seeds in a piece of aluminium
foliage and add a few drops of the solution. Close the packets, stick
on a label and put all the labels upright in a pot with sand. This stays
on room temperature for 24 hours and then I sow the seeds.
When the seeds stik together, I use some fine sand to seperate them.
The seeds must be very clean or you may get mould or you may need to reduce the time that the packets remain closed.
- Great seedpots of clay (in the ground) or plastic pots (on the ground ) all filled with a soil based mixture (acid or lime). Great seedpots mean a more stable situation in the seedpot and the possibility for the seedlings stay longer, but the pots need more room.
- Pots in the greenhouse with a lot of ventilation (some glass panels are removed) and a sprinkler system to increase humidity when the temperature is rising (the results with watering from below were less efficient for the treated seeds), in summer 3 times a day for 1 or 2 minutes, depending on how dry it is.
- Early April seems a good time to
sow treated seeds:
more light, less chances for frost (after germination the seedlings are rather weak), higher temperature (hormones are working better), still enough time to grow.
- The upper part of the glasswindows of the greenhouse are almost always white washed when the sun starts to burn.
- Germination usually starts after 10 days for the gentians except for the G. bavarica species. They still have a delay of one year at the most. With G. terglouensis ssp schleicheri, there is even germination possible after 2 years. Sometimes there is no germination, but it is always possible that the seeds are not viable.
- The seedlings mostly stay in the seedpot till the following spring (unless they are too big), then a part are planted directely in the garden and the rest in pots (still soil based mixes) of 10 cm. I wait this long because the seedlings are weaker than untreated ones. They are sometimes etiolated. Some gentians which are growing faster like septemfida, cruciata, calycosa, pneumonanthe, boissieri ... are planted out the same year.
- After a month I start liquid feeding.
- About 1000ppm for gentians : my experience is that you can have more seedlings but also more losses because they are weaker.
- It would be interesting to use different solutions. There will
probably be an ideal solution for each group of plants, but to discover
this you need to have a lot of time.
When the solution is ready it should be used as soon as possible because it loses its strength .
- The powder must be kept dry. In that case it can last for many years. Normally I use 20 mg to treat all the seeds that I want to treat during one season, so 1 g is sufficient for many years.
- I don’t treat all the seeds. When I have the gentian seeds before New Year I sow part of them immediately, so that the cool period (less than 10°C) is long enough to stimulate germination. If there is no germination in April, I can treat the rest. Some gentians may even be sown untreated in February with good results.
- Seedpots treated or not are always kept for three years.