NEIGHBORHOOD GARDEN FOR MARCH 12, 2016 *************************************************************





          Several of my Master Gardener friends take care of yards for other. As we talk I hear a common word, “mulch”. What does it do? Here in Nebraska where it often becomes hot and dry, it becomes more and more important, especially when we have the threat of water rationing.

          My favorite mulch is small bark.  I find it easier to walk on and to drive my wheelbarrow over. There are also smaller spaces for weeds to escape from below so several inches prevents their sprouting or doing well. The soil will keep its moisture longer as well as keeping it cooler.  If you have a ring of it around your trees, you are less likely to scar that trunk with your lawn mower.

          So what do you use and how do you mulch?  Most gardeners I talk to say 2 to 3 inches is enough to do the work and let the rain get through. More than 3 to 4 inches does not let air down to the soil and to the roots of your plants. You will need to add more each spring as it breaks down and becomes part of your soil. Grass clippings contain nitrogen fertilizer but they can smell badly and let water run off. When I use it, I like to put it under my bark chips.

          Mulch can also prevent splattering of mud on your leaves. Be careful about putting mulch up against your plant stems or you can cause rotting.  Instead leave a ring of an inch or so away from the stems.

          So what do you use? It will depend somewhat on what you like to see! Peat moss gets dry and causes run off so I never use it for mulch. But it can be mixed with a coarser material. Acid peat is quite often used to lower the pH in AZALEA’S, RHODENDRONS, and BLUEBERRIES. My soil usually tests about 7.2 (slightly alkaline) while many of my plants prefer 6.5 to 7.0 (neutral). You may have heard that pine needle mulch will acidify the soil. This is true only of fresh ones. Sulfur granules are my favorite additive to lower pH but it has to be done again and again. You can get a pH soil tester to check your soil. If I want acid soil in my pots, I fill them in the fall before, add soil, then add the granular sulfur, and mix well so it will be ready by spring.  There is also Miracid fertilizer (and other brands of acid fertilizers) you can get for your house plants.

          Mulch can also increase the organic content of the soil (humus) which is desirable. So what do you choose? Straw has little food value. Sometimes I put a light layer of nitrogen fertilizer down under straw mulch to feed the plants until the mulch breaks down. Leaves that have been ground up by a grinder or by your lawn mower work very well as mulch and also have food value when added to the soil. Do not use leaves on top of the soil that have not been shredded, as they tend to mat and the water runs off.

          Organic mulches such as manure, bark, and compost are very desirable. When you add compost, if you have a good worm supply, they will find the compost and take it down deeper in the soil as it goes through their digestive system and then deposit the “worm castings” into your soil and aerate your soil at the same time. A number of gardeners here in Lincoln get compost from the city landfill and use it as mulch as well as fertilizer.

          Mulches of gravel and sand are used in rock gardens or around plants that are sensitive to water on their leaves. In pots this also done as a decorative effect. I also use it to prevent water from splashing on my leaves when I water.

          Mulch should be long lasting, and not easily be moved by rain or watering, as well as being loose enough to allow water to get through. I like compost because of its food value but its light and washes away easily so a thin (one inch) of compost just under my bark chips works very well.

Copyright 2016