Sparaxis Bulb Care

Johannes-Ulrich Urban via pbs pbs@lists.pacificbulbsociety.net
Sat, 01 May 2021 06:43:35 PDT
Hello Sylvia,

After what you write, I would bet that your bulbs are starving. For how long have they been in the same substrate? Which substrate do you use? How big, how deep is the pot? Have you fertilized them?

Sparaxis are easy and straightforward bulbs, I have had maiden flowers this spring from Silverhill seed grown Sparaxis tricolor from a November 2018 sowing. I cannot over emphasize that bulbs are hungry and very much benefit from fertilizing, especially towards the end of the growing season. I fertilize three times during the growth cycle of winter growing bulbs using a balanced low nitrogen fertilizer. First time when the new shoots are clearly visible in order to give them a good start. Second time before flowering and third time after flowering even if the leaves already get a yellowish tinge. With bulbs, fertilizing shortly before dormancy is not detrimental as it would be in woody plants. Woody plants might be stimulated into soft new growth which would succumb to a cold winter. But bulbs would not extend their growth cycle in a negative way due to fertilizing.
Another reason for bulbs just surviving but not performing might be that they dry out in the middle of the growing season. This is related to pot size. Small pots dry out faster than big ones. If a bulb dries out prematurely during the growth cycle it will not die but it will enter what I call an emergency dormancy. This saves its life but the resulting bulbs will be small. This process of entering premature dormancy cannot be reversed by good watering once triggered by drought.

Maybe it is a combination of several factors? Do your seedlings get enough light?

What can you do? I think several years old Sparaxis corms should be big enough not to be missed when you tip out the contents of the pots once they have gone fully dormant. You could then repot into new compost into a bigger pot. I am only guessing because I do not know the pot size they are in right now. Don’t store small bulbs or corms dry in a bag for a long time, it is better to replant straightaway and then keep them dry in the compost  in the pot.
Do you have to grow them in pots? Depending on the climate you live in planting them into the garden might be a good option if they are not too small. 
If you should find the bulbs are too tiny to handle, then put the whole content back into a bigger pot. New compost first, then the entire content of the old pot  and top up with extra substrate.

Hope this helps,

Bye for now 

Uli 
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