Organic Gardening Tip of the Week

As fruit and nut trees go into fall, shorter days and cooler temperatures stimulate a hormone which triggers the trees to go into dormancy and stop growing. Cold temperature breaks down that hormone and when the tree experiences enough cold temperatures, dormancy is broken and the tree starts to grow again, by flowering and developing leaves. The period of cold temperatures needed to break dormancy is the cumulative chill hours, temperatures between 32- 45°F from November to February. What happens if your tree does not get enough chill hours? The tree will produce leaves later, blossoms may not open or just drop and therefore your fruit tree will not produce fruit. One the other hand why not just plant trees that have a much lower chill requirement? If you plant low chill trees in a high chill area your trees will break dormancy too early and the blossoms will be killed by cold temperatures and you have the same result, no fruit. Chill hours needed are not an exact number, it is usually a range. If you don’t know the chill hours in your area, consult your local Farm Advisor, Master Gardener or even a local nursery may be able to help. We have an article on chill hours, however, the links included to find your chill hours are only for California counties. If you live outside of California, you will need to search the internet to find sources, weather stations or county Ag Offices that can assist you. There is another site you can use, but it will take a little bit of work since the chill hours can only be looked up 10 days at a time. But once you get your chill hours calculated you are done. Might want to look at chill hours for several periods, since it does fluctuate. Just start from November 1 and go through February of the following year.

Raspberries really benefit from winter pruning. Once the second year canes fruit they will die and can be cut back right after fruiting or in the dormant season. Remove damaged, weak or dead canes by pruning at ground level. Leave canes that are robust (about 1/4” in diameter), but thin out canes to about 6” apart. You should keep your raspberries to about a 2’ wide hedgerow. Since raspberries spread by underground runners, the berry patch can get quite large if not thinned out. Dig up any plants that have escaped the 2’ wide row. You can either plant these in another area of your yard, share them with friends or put them in your compost bin.

Blackberries have three possible growth habits—erect, semi-erect or trailing. The way to train and prune them will depend on the type. If you did not top the new canes during the late summer, you should top them to about 5’ (or the height of your trellis or fence). Dormant pruning of erect blackberries entails removing dead canes (color is brown vs a newer green cane) and cutting back laterals to 12–18”. Semi-erect blackberries should be thinned to 5 to 8 of the strongest canes, shorten the laterals to 12–18” and remove any growing on the lower 3’ section of the main canes. Tie to a fence or trellis to provide support. Trailing blackberries are less cold tolerant and in cold regions the canes can be left on the ground and protected with rowcover or mulch over the winter. In spring the canes can be lifted and tied to a trellis at 3’ and 6’.

Now is a great time to plant your fall flower bulbs for a dazzling spring display of color. If you live in cold winter zones (1-7), you can plant when the soil has cooled to at least 50°F and your ground is still workable. For areas with warmer winters (zones 8-11) you may not get enough cold temperatures for the bulbs to do well, so the bulbs can be placed in the refrigerator–but not by any fruit that may give off ethylene gas. Bulbs do not need more than about 11-15 weeks of chilling, and the good news is that we store our bulbs in a cooler until they have shipped out, so they have already chilled about 8 weeks! Plant your bulbs in areas that have good drainage, they will not do well sitting in soggy soil. They also like full sun, so since they bloom in the spring when many trees may have not leafed out, you can plant them almost anywhere in your yard!

Follow the planting instructions on the package, and make sure you plant pointy side up. Some bulbs are kind of hard to figure out what is the bottom, so if you can't tell, plant it sideways and the bulb will right itself. No need to fertilize at planting time for new bulbs, but come spring you should give them some quality bulb fertilizer so they will have enough nutrients to return another spring bloom.

If you don’t want to wait until spring for your blooms, many bulbs can be forced to bloom in the winter indoors. For more information on forcing bulbs, read our article “Forcing Flower Bulbs”.