What's Up In The Garden

What’s Up in the Garden, by Jackie Dohlman, Franklin County Master Gardener

Tips on Starting Eggplant Seeds, Soil Mix for Raised Beds, Pruning Blueberry Plants, and Black Knot Fungus

When should I sow eggplant seeds indoors?

Eggplant seedlings should be planted in the garden after the danger of frost is past. Eggplant can be planted outdoors in mid-May in central Iowa. Gardeners in southern Iowa can plant aboutone week earlier, while those in northern counties should waitone additional week. The last practical planting date is June 20. When starting plants indoors, sow seeds six to eight weeks prior to the anticipated outdoor planting date.

What would be a good soil mix for a raised bed?

An excellent soil mix can be prepared by mixing equal parts topsoil, organic matter (compost, well-rotted manure, or peat) and coarse sand.

Before filling a raised bed, work up the existing soil with a rototiller or spade. Add a few inches of the soil mix, then incorporate it into the existing soil. Continue to add and incorporate additional soil mix until the raised bed is filled. Incorporating the soil mix into the existing soil prevents the formation of distinct layers in the raised bed. Distinct layers of soil may impede water movement and discourage root growth.

What is the proper way to prune blueberries?

Blueberry plants are small to medium-sized shrubs. Blueberry yields and fruit quality decline when blueberry shoots (stems) reach five years of age. In late winter/early spring, prune out any dead or diseased stems. Also, prune out stems that are five years old and older. Allow one to two new shoots to develop each year.

There are black growths on the branches of my chokecherry. What should I do?

The black growths are probably black knot. Black knot is a fungal disease that occurs on chokecherry, European birdcherry, and several other wild and cultivated cherries and plums. The black swellings can vary from a few inches to a foot or more in length.

Black knot is caused by the fungus Apiosporina morbosa. Fungal spores produced on one-year-old and older galls initiate new infections. The knots are soft when newly formed and later become hard and black with age.

Black knot is difficult to control. If only a few galls are present, prune out the infected branches in late winter. When pruning, make the cut at least three to four inches below the gall. The pruned material should be removed from the area and destroyed. Several fungicide applications may help prevent future infections.

The fungicide applications should begin just before bud break and continue until after fruit set. Attempts to control black knot in badly infested trees are not likely to be successful. When dealing with severe black knot infections, the best options are to do nothing or remove the tree and replace it with a black knot resistant cherry or plum.

Got gardening questions? Contact the Hortline at (515) 294-3108 (Monday - Friday; 10 a.m. -12 noonand 1 - 4:30 p.m.) or send an e-mail to hortline@iastate.edu. For more gardening information visit us at Yard and Garden Online at www.yardandgarden.extension.iastate.edu

Picture courtesy of audreyjm529 over at flickr.com  See what's going on in Hampton!