I would like to save Canterbury seeds for propagation, but don't know where to find them or what they look like.
Many of these plants self-seed but if you still want to keep some in the event they don't, just wait until the blooms have dried up and collect the flower heads. Then you can harvest the seeds and plant them right away or save them for planting the next season. Here is more information on growing these plants: https://www.gardeningknowhow.com/ornamental/flowers/canterbury-bells/canterbury-bells-plant-how-to-grow-canterbury-bells.htm
When should I plant out my canterbury bell plants into the garden? The canterbury bell seeds I set in trays in my greenhouse are now ready to prick out when they are large enough. When should I plant them out?
If they have their first sets of leaves, they should be ready to transplant out but you may want to harden them off first. These articles will also help: https://www.gardeningknowhow.com/ornamental/flowers/canterbury-bells/canterbury-bells-plant-how-to-grow-canterbury-bells.htm
It is the first time that I have grown Canterbury bells. first year produced only leaves. This year I have enjoyed a vast array of colour; however, they have now finished. I wondered whether I should deadhead as they have thick stems. Also, when should I expect my next blooms?
Kind regards, Steph
Yes, deadheading is always a good thing, and you may even want to save some of the spent flower heads for seeds next season. Here is more information: https://www.gardeningknowhow.com/ornamental/flowers/canterbury-bells/canterbury-bells-plant-how-to-grow-canterbury-bells.htm
I have planted seeds indoors twice and both times they grew half inch then died. I am using regular soil.
When seeds germinate and then the seedlings wilt and die it could be due to a condition known as "damping off" disease which is caused by a soil-borne fungus. If you used soil from the outdoors the soil may have contained fungus spores. I would start over with sterile soil (potting mix) in clean pots. If reusing the same pots sanitize them with bleach (1 part bleach to 10 parts water). Give your seedlings plenty of heat and light, and be sure not to overwater.
For more information on "damping off", please visit the following link:
Since you successfully germinated the seeds indoors, then they died, most likely they either had too much, or too little moisture, and or light sources were not correct.
The seedlings need to be kept damp. A good soilless potting mix, specifically for seed starting is preferred for starting seeds.
Most indoor lighting is not sufficient for seedling growth, and the addition of grow lights is necessary.
Here are a few links to help you get started.
My canterbury bellflowers seem to be fading in color. Is there something I can add to the soil?
This article should help: https://www.gardeningknowhow.com/plant-problems/environmental/fixing-color-faded-flowers.htm
I planted a "packet" of Canterbury Bells seeds about 6-8 weeks ago in a long trough-like pot in an indoor greenhouse with a light. The seeds successfully have come up and look like mini parsley right now in a long row. Should I be transplanting these outdoors at this point or should I leave them in the pot? They are no more than 1 inch tall and I'm in USDA zone 6. Thank you
You can go ahead and transplant out to the garden, but make sure you harden off the little plants prior to putting into the garden.
Here are some links with more information.
Should you remove dead flowers?
Yes, deadhead the spent flowers.