WSU Extension Q&A: Not too late to plant dahlia tubers

Q. Am I too late to plant dahlia tubers in the garden? I just remembered a friend gave me some last fall after she dug them from her garden.

A. No. It is best to plant dahlia tubers after the soil warms and the danger of hard frost has past, typically about May 1 for the Tri-Cities. Get the tubers out of storage and discard any that are rotten. If sprouts have started, cut them back to about 1 inch in length. Prepare the planting bed by working up the soil and adding organic matter. Then place the tubers horizontally in 5- to 6-inch-deep trenches and cover with 2 to 3 inches of soil. As the plants begin to grow, continue to fill in the trench until the soil is level.

If planting taller varieties, set your stake at planting time so you don’t damage the tuber. Many of the showy dahlias need staking to keep them upright, especially considering our windy days. Mulch lightly with an organic mulch like compost or fine bark.

Q. I would like to grow some red, yellow and orange peppers. Do the green ones turn color or do you have to plant a specific color?

A. Most peppers start green and then turn red, yellow or orange. Patience and an early start are the most important factors for producing red peppers. Start plants indoors, and choose varieties that mature earlier in order to produce peppers other than the color green.

Q. How does the growing degree days (GDD units accumulated) for alfalfa compare with previous years?

A. The growing degree days for alfalfa are figured with the base temperature of 41 degrees. The formula for calculating: average temperature (maximum temperature plus minimum temperature divided by two) minus 41 equals growing degree day units for each day. If accumulated these from Jan. 1 to April 17 and add them together, you have the number of GDD units accumulated.

In 2015, at least one farmer I know of started their first alfalfa cutting in the lower Basin by the end of April, which was at 823 GDD units. They may start even earlier this year. In contrast, parts of Colorado got up to 47 inches of snow April 17. The average growing degree day units accumulated at WSU Tri-Cities from 2008-15 was 443.

This story was originally published April 24, 2016 at 7:17 AM with the headline "WSU Extension Q&A: Not too late to plant dahlia tubers."