Cyclamen Potting Medium

Roy Herold
Sat, 27 Jul 2013 06:17:36 PDT

Thanks for the reminder--I really need to repot some of my cyclamen, too.

I have more or less abandoned growing coum and hederifolium in the 
greenhouse, however. After an initial period of doubt and caution, I've 
found that they grow much better in the ground outdoors. They never seem 
to be all that happy where I plant them, but the ants seem to distribute 
the seeds to perfect locations. No worries about hardiness, either. 
We're pretty much in the same zone, and you should have the same 
experience. Yeah, you don't get to enjoy them in the greenhouse, but 
that's a small sacrifice to pay for seeing them look so much better in 
their element. Hint: find a north facing location.

All of my purparescens and cilicium are outdoors, too, with similar results.

That said, rohlfsianum are my favorite cyclamen, and I think I grow them 
reasonably well. My oldest plants are just over twenty years old, with 
tubers that weigh around five pounds without soil. In general, I don't 
repot until they break their pots, which seems to happen with alarming 
regularity. Do not overpot--an inch between the tuber and pot is more 
than enough! I would recommend a soil mix with more sand and grit than 
might be used for hederifolium and coum. I keep terrible records with 
regards to soil mixes, but if I was repotting rohlfsianum I'd use one 
part peat/coir mix (Metro 380 or equivalent) to one part perlite, one 
part grit/pumice, one part coarse sand.

Please, please do not plant the tubers too shallow! Rohlfsianums root on 
the top surface of the tuber (as do hederifolium). It really pains me 
when I see photos of exposed tubers--this is not how they want to grow. 
Put at least an inch of soil on top, preferably two, followed by a top 
dressing of another inch of coarse gravel (1/4" to 3/8").

The other thing about rohlfsianum is that they have huge leaves (I've 
seen them 8" across) that transpire a LOT of moisture in our dry 
winters. They dry out quite rapidly, so for the larger ones I use big 
plastic pots placed in deep saucers. The best way to water is to fill 
the saucers to the brim in addition to giving to top watering. There is 
no such thing as overwatering rohlfsianums in the winter! Even a plunge 
bed may not be able to keep up.

My second favorite greenhouse cyclamen was received as africanum, but is 
most probably x hildebrandii, a hybrid with hederifolium. To me it is 
far superior to either parent. It starts blooming in late August, and 
continues non stop through December. At peak, it has at least 200 
flowers open at a time. The leaves and flowers go straight up from the 
tuber, and don't have that annoying habit of going out to the edge of 
the pot before deciding to emerge. This has a tuber that is pushing ten 
pounds. Potting is similar to rohlfsianum.

Most of the tender cyclamen spend the summer under the bench in the 
greenhouse with no intentional watering, and go outdoors at the 
beginning of September, earlier if they show growth.

Off to the potting bench now...


NW of Boston
Zone 6-ish, was 5, headed for 7
Cool greenhouse, 38F

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