Crocus bulbs produce beautiful purple, yellow or white flowers. They belong to the Iris family and can be grown indoors. Crocus are actually “corms”. A corm is similar to a bulb in that it’s a thick stem that acts as storage for a plant to survive the cold winter months.
To grow crocus flowers indoors, you need to “force” the bulbs. This may sound very technical, but forcing simply means tricking the bulb into thinking it’s time to bloom. How do you do this? The crocus bulb blooms in spring after being planted in autumn and living through the winter. To force them, we need to:
- Pot them
- Cool them to simulate winter
- Put them in indirect light to simulate spring
- Put them in direct sun
Pretty straightforward, isn’t it? Let me go through that in a bit more detail.
You should start the forcing process 3 to 4 months before your target bloom date. Select a pot (with some holes for drainage) and an appropriate potting mix (containing sand, soil and peat moss ideally). Your aim is to have the tops of the bulbs poking out slightly above the soil. Put in the first part of potting mix to a height that’ll allow the tops of the bulbs to poke out. You can use a couple of bulbs. Put them next to each other, almost touching, with the flatter side of the corm facing down. Add the remaining potting mix so the tips of the bulbs are exposed and then water generously.
You need to cool the bulb down to between 4.4 and 10 degrees Celsius (40-50 degrees Fahrenheit). If you’re doing this out of season when it’s warmer than that, you’ll need to put them in the fridge. Keep them at this temperature for about 12 weeks. Check on it weekly and top of with a little water if necessary to keep the soil moist.