Growing canna from seed is pretty straight forward, first of all you will need some seeds. These can be purchased from seed suppliers. The majority of which have an on line presence. Or you can collect seed from plants you have already grown.I generally begin growing Canna from seed just after valentines days (14 Feb). Light levels begin to increase at about this time. In the past, I would make a start as soon as the Christmas dishes had been washed. However, January can be a miserable month for a newly germinated canna plant.
- A pair of heavy duty toenail clippers.
- Clean plastic flower pots (3 or 4 inch).
- Some multipurpose compost.
- A small stemless glass (for stability reasons).
- Some canna seeds.
First step in growing canna from seed involves chipping the seed. Canna seeds have a very hard coating which wears down over time in a moist environment. If you simply planted the seeds, whole, germination will be more unpredictable. The plants have obviously worked out when is the best time for their children to emerge in the wild, but we are not interested in all that. By chipping the seed you are in control of timings.
A certain amount of pressure needs to be applied to scratch the seed coating. You do not want to go too deep, just until you can see the white inside.
This may take a little practice. The seeds have a tendency to fly off all over the place. If they hit a solid floor they tend to bounce and disappear under the furniture. Chose your location wisely.
Next, once you have chipped all the seeds they need to be soaked. This is where your small stemless glass comes in. Cover the seeds in water and leave for about 48 hours. If you forget about them for an extra few days it does not seem to matter.They just start to grow in the glass.
After a couple of days in soak, they need to be planted. They can either be planted in individual cells trays or in 3 - 4 inch flower pots. Using individual seed trays removes the need to prick the seeds out, i.e. untangle all their roots and plant individually when they are a bit older. However the germination success rate seems to suffer. So if you only have a limited amount of seeds I would plant them in plastic flower pots. I would also only plant a maximum of 4 or 5 to a pot. This is to reduce the headache of untangling the plants when they need their own pots.
Before planting I like to sterilize the compost. This is to kill off any fungal spores that may wish to attack your babies as they emerge. My preferred method is as follows:
Fill the clean flower pots with a multi-purpose compost (new shop bought stuff, don't use any old rubbish left over from last year!). I like to use boiling water to sterilize the compost surface. Fill a small (pint sized) watering can with a fine rose attached, with boiling water. Water this onto the compost. Using a fine rose prevents an uneven surface. A small watering can prevents you pouring boiling water all over the kitchen floor or onto your legs.
If you do this an hour or so before planting, the seeds will benefit from having a nice warm pot of compost. The compost will also have drained any excess water and be at just the right level of moisture. Pop the seeds in evenly and not too deep.
Next put the pot into a medium freezer bag and seal the top. This way you do not have to worry about the compost drying out. Keep the pot in a warm place but not in direct sunlight. Wait a few days and you should have something like this:
Once the majority of plants have emerged the bag needs to come off. If you have a frost free greenhouse put them out in it. If you do not have such luxuries, they will grow on a window sill. Make sure the plants are rotated regularly or they will grow side ways. Before I had a greenhouse I found that plants grown indoors would get sun burnt when I put them outside in the spring. You will need to acclimatise your plants to outside by leaving them in the shade for a while.
As your plants grow they will need to be separated and planted up individually. Soak the pot thoroughly. This makes the compost soggy and then it is easier to pull the plants apart without too much damage to the roots.. Re-pot the plants individually in small pots. Do not think you can save time by planting them in large pots. For some reason the plants do not like this and often languish. Pot up when you see the roots emerging from the base of the pot. Think of it like changing gear in a car. If you change up too soon, the car struggles. If you change gear at high rev's the car accelerates away nicely.
Plants grown in individual cells need potting on once they have reached this stage:
And then again once they are at this stage:
And that will be their final potting on before they go out into the garden full time. So typically a canna grown from seed will have been in three pots before planting out.