A: Think of what ecosystem the plants came from and what kind of ecosystem you are recreating in your flowerbeds. If it is a northern woodland plant, it would have had a loose soil with lots of debris on top, so bark or pine needle mulch is fine. A loose layer of any organic material will help retain soil moisture and reduce weed growth. As the material decays, it will help form a good organic soil.
Prairies do build up organic matter on the soil that decays, but it is not woody material. If you have a bed of native grasses, they will accumulate their own mulch of dead grass blades. Flowers and grasses from prairie areas benefit from any kind of mulch that helps retain moisture and slowly decays into soil, even if it is a woody mulch.
If you have plants from dry, sandy soils – such as desert plants – they would be used to less organic matter accumulating on the soil and typically they wouldn’t need mulch that retains water around the roots.
Q: Are pine needles OK to use as mulch in a garden? I had heard that they may not be good, as pine needles under a tree tend to kill the grass and other vegetation.
A: Pine needles make fine mulch. One of the points of mulch is to keep other things from sprouting, and pine needles in sufficient depth will help do that. Dead needles don’t release chemicals that kill existing plants; plants under pines die from fresh needles releasing chemicals and the tree blocking out the light.
They do help to acidify the soil, if used over and over again over the years. In some areas of the southern and western states, you can buy bales of pine needles to use as mulch, where it is often called pine straw.
Just use a layer 3 to 4 inches thick and never, ever pile any mulch onto the trunk of any tree or shrub.
Q: How do I dispose of the rinse water when I clean my garden sprayer? I used a fungicide.
A: Let me answer this in two parts. There are two containers involved here. The first one is the container the product came in and the second is your sprayer.
Pesticides come in glass, plastic and paper containers. If the product being used is a liquid and you are down to the end, the proper thing to do is let the container drain into the sprayer for at least 30 seconds. Then fill the container until it is a quarter full with rinse water and again drain it into the sprayer for 30 seconds. Repeat the rinsing three times. The container is now considered clean enough to be disposed of in normal landfills or in recycling. The container should never be reused for any purpose and if possible, it should be punctured so no one can reuse it.
Paper containers that can’t be rinsed should be gently shaken over the sprayer, but not so much as to create a cloud of dust you could breathe in. The container is now considered prepared for disposal.
When preparing your sprayer for use, you should decide how much pesticide is necessary to cover the whole area and not mix it up too much. The only proper way to dispose of any extra is to use it according to the directions on the types of plants it is registered with the EPA to use it on.
Once you are done using up all the pesticide, you need to rinse the sprayer. All diluted pesticides and rinsates need to be disposed of with a minimal impact on the environment. Rinse the sprayer the same as the container – using small amounts of water three times. Each time, the best thing to do is to spray the rinsate onto the treated area or appropriate plant material, even if the pest is not present.
You cannot drain the container or sprayer into any location that would allow even small amounts of pesticides into the municipal or natural water systems.