47 September 23, 2006
The meteorologist have told us that we could get a frost in Western Massachusetts this past week. Although it seems we are in the clear for frost, it will happen sometime in the not too distant future. A frost will mean that it is time to dig up and store for the winter most of the summer flowering bulb. This would include dahlias, gladiolus, begonias and cannas. I have had a few people ask me how to do this fall chore, so here goes.
Summer flowering bulbs are usually dug up after the frost kills the top growth. If the first frost is forecast to be a hard freeze, you will need to dig up the bulbs before the ground freezes. If the bulbs are allowed to freeze, then the bulbs will die. Once you have dug up the bulbs, take a garden hose and wash off any dirt that remains on the bulb. Once the bulbs are clean, you will want to store then for a few days to allow the skin of the bulb to dry off. Remember, you should store the bulbs in an area where the temperatures will not drop below freezing. If the bulbs freeze at this point, you might as well throw them out. Once the bulbs have dried for a few days, you need to check out the bulbs. If you see soft spots or deep cuts in the bulb, it is best to throw that bulb out. Soft spots are signs of rot and could spread to other bulbs during storage. Deep cuts could be an entry point for diseases that will cause the bulb to rot. If you are looking at dahlias, you will notice that the dahlia is a cluster of rhizomes that look like sweet potatoes. If one of the rhizomes is bad, you can cut that rhizome off of the clump and throw that part away. You can then store the rest of the rhizomes.
Once you have allowed the bulbs to dry a bit, you can cut back any of the remaining top growth on the dahlias. You will want to leave a short stem at the top of the rhizome cluster. Top growth should break off of the glads and begonias. If not, allow the bulbs to dry a bit longer. Cannas would be treated the same way as dahlias. Once you are sure that the bulbs have dried off after washing, and then you can prepare them for storage.
Before you store the bulbs, it is a good idea to dust the bulbs with a bulb dust. The dust contains a fungicide and an insecticide. This helps to prevent any problems with insects and particularly diseases while the bulbs are in storage.
Summer flowering bulbs do not have a thick skin. This makes them susceptible to drying out in storage. The bulbs need to be covered to prevent the dry air of winter from pulling all of the moisture out of the bulb. When I need to store bulbs, I will take a box and add a 1-inch layer of vermiculite to the bottom of the box. I will then place the bulbs on the vermiculite, making sure that the bulbs do not touch. This is done in case one bulb starts to rot in storage. Doing this lessens the chance of the rot spreading to other bulbs. The bulbs are then covered with a couple of inches of vermiculite. Surrounding the bulbs with vermiculite protects the bulbs from the dry air. You can use other things instead of vermiculite. Dry peat moss, dry sand and perlite can all be used as the insulating material. Avoid using soil. Soil can contain the diseases that will cause the bulbs to rot in storage.
Once you have the bulbs covered, they will need to be stored in an area that won’t go below freezing, yet in an area that won’t be warm either. A crawl space in the cellar or in a closet that has an outside facing wall all work well. The trick is to not allow the bulbs to freeze while not allowing then to be exposed to the warm and dry temperatures of the main part of the house. If you have done everything right, come spring you will have bulbs that you can plant in your garden.
Well, that’s all for this week. I’ll talk to you again next week.