Welcome to the first edition of the Rural Intelligence Question of the Week! Every Monday, the Master Gardeners of Western Massachusetts come to the Garden from 9am – 12pm to answer gardening questions. We’re picking a question each week and writing about it for the Garden section of Rural Intelligence. RI is an amazing online resource for the Berkshire/Hudson Valley area that is published each week that features local events, reviews, restaurant listings and articles related to life in our neck of the woods. We’re thrilled to be a part of their team!
What’s the deal with mulch – do I really have to apply it to my garden? If so what kind? When? How much?
Well, you don’t have to apply mulch to your garden. Then again, you don’t have to shower everyday either, but that doesn’t mean that it’s not a good idea. The truth is that just about every kind of garden likes a nice layer of mulch and for good reason. There are a ton of benefits, and though it might seem like a lot of work and expense up front, in the long run it will end up saving you time and money. Here’s how:
Mulch protects your soil. When it comes to your garden, it is all about the soil. Having good soil quality in your garden is critical and good soil is worth protecting. That’s where mulch comes in. It protects your soil from erosion and helps prevent compaction that comes with garden equipment and foot traffic from both people and animals. When soil gets compacted, it limits the amount of large pore space that allows for both oxygen and water to move into and through the soil. Low oxygen levels are a significant factor in reducing plant growth that most people aren’t even aware of. Mulch provides a layer of “cushion” that reduces the impact of traffic around your plants.
Mulch reduces moisture loss and protects from high temperatures. We all know how important water is to a garden. Keeping moisture in the soil is just as important as getting water there in the first place. This is where your mulch steps in. It prevents sunlight from reaching the surface of your soil – that keeps the temperature down, which in turn, reduces the rate at which the water evaporates keeping that moisture where it belongs – near the surface of the soil where plant roots like to grow, not bake in the sun.
Mulch keeps away weeds and adds some “wow” . This one’s a real crowd pleaser. Keeping light off the soil surface not only reduces the rate of water evaporation, it also prevents weeds from germinating. Less weeds not only mean less work for you, it also means that the plants you do want growing in your garden are not competing with weeds for soil nutrients and water. Plus, mulch just looks nice!
Different kinds of mulch: You don’t necessarily need to run to the hardware store and spend a lot of moolah on mulch as many organic materials are good mulch options: straw, shredded/chopped leaves, and pine needles are some examples.
Crushed stone or gravel is good for use around beds, walkways, steps, rock gardens and foundations. To prevent the stones from migrating down into the soil, use an underlay of synthetic fiber (weed cloth) or black plastic mulch. Be aware that limestone chips raise the PH of soil and should not be used around acid-loving plants. Black plastic mulch is also a good, stand alone mulch option for vegetable gardens and crops.
As for the choices of mulch you find at your local nursery or hardware store, these are usually shredded bark and wood mulches. Light or dark choices make no real difference, however we try to avoid mulches that contain dyes and chemicals as a personal preference (think red mulch.) You may also want to inquire where the mulch you are purchasing came from. One of the most popular types of wood mulch is Cypress, which has resulted in the clear-cutting and destruction of precious wetlands in Florida and Louisiana. With all of the mulch options available today, there is no need to sacrifice the beauty of one landscape for another!
How to apply mulch. Apply mulch in about a 3” layer after the soil has warmed and fertilizer has been applied (around here, plan on mulching near Memorial Day.) Be sure to not bury any plants; mulch needs to be 3’-4’ away from the plant crown to prevent rot and disease. (This includes tree trunks!) Buy good quality mulch to avoid potential problems such as sour mulch or artillery fungus. “Souring” occurs when hardwood bark mulch is allowed to stand in big piles for long periods and begins to compost without an adequate air supply, resulting in extreme acidity that can burn your plants.
You may want to check with your local municipality as they will often have “chip” piles or municipal mulch that you can use for free. If you have large spaces that need mulching, it may also make sense to research having mulch delivered by the cubic yard by your local garden center or building supply shop. It is often cheaper and easier than buying it by the bag.
Do you have a gardening question that you need answered? Call the Master Gardener’s hotline at the Berkshire Botanical Garden: 413.298.5355