Poinsettias sensitive to changes in weather

QEarly in the spring, I cut back my poinsettia plants and repotted them in fresh soil. When the weather turned warm, I put them out in the bright shade of the patio for the summer. They grew very well. When should I bring them back indoors? Will the top bracts turn red automatically?

A: About a month ago would have been ideal timing for a smooth transition back into the house. Poinsettias are particularly finicky about temperature fluctuations. The trick is to bring the plants back into the house at a point when overnight low temperatures are approximately the same indoors and out. It’s best not to wait until outdoor overnight lows dip far below what they are in the house.

Subjecting plants to an abrupt change in night temperatures often causes them to drop leaves. This is a common complaint about house plants brought indoors after nights have turned decidedly cool. At the same time, the plants often must adjust to dry air and insufficient light. Ideal for poinsettias are temperatures between 15 and 21 C, and a soil kept just modestly moist.

For full colouring in the plants at Christmas time, they need to be located from the beginning of October onward where no artificial lighting will be on from dusk to dawn. A general rule of thumb is 10 weeks of 10-hour days (that is, 10 daylight hours) to produce a colourful plant for the holiday season.

QShould the top rosettes of leaves on my Brussels sprouts plants be cut off or left on the plants?

A: It’s a common practice to remove that top cluster of leaves in late September, to hasten development of the sprouts below. Halting that topmost growth turns the plants’ energies into sprout development.

Try washing, trimming, and steaming the removed topknots. Serve with butter, salt and pepper for a delicious and nutritious vegetable.