(A college friend, who happened to be fluent in German, obtained a t-shirt via thrift store that simply stated “carpe mulchem.” To this day we’re still not sure what it actually means, but believe the literal translation is Seize the Mulch – which of course makes absolutely no sense and therefore we thought it was awesome.)
It’s time to seize the mulch! Maybe you’ve been feeling behind because you haven’t gotten to mulching your garden beds yet? (You know, because of the recent snow we’ve had within the first few days of spring?!) Welp, I have great news. Mid-May is the ideal time for putting down your mulch! Take full advantage of early spring mulch sales, but just wait to actually put it down.
Here’s why. Soil temperatures: It isn’t until mid-May that the soil levels has warmed to about 55˚. It’s this 55˚ mark we’re aiming for, so that our roots can grow and thrive. 55˚ is warm enough to put that mulch down and the mulch will help keep the soil temperatures more temperate (instead of spiking during the day and dipping low during the night.) Mulch will also help insulate the soil and keep it from getting hot during the summer. Moisture: that’s right. Mulch will help keep all this spring rain we’ve been receiving in your soil. Mulch acts as a barrier and slows moisture from evaporating from the surface of the soil. HOWEVER (yes, this is a literally and figuratively a big point) if mulch is put down too thick (more than 2”) than this mulch barrier will compact and restrict air flow, as well as becoming water impermeable a.k.a. water proof. If you put mulch down too thick, your mulch will act as a barrier to water, not letting it seep into the soil, but rather, run off. This is bad. Really bad. One definitely does not want WATER IMPERMEABLE SOIL. Those plants, whether newly planted or well established need that rain water just to survive, let alone thrive!
More reasons not to mulch over 2” thick: 1. Another great reason not to put your much down any more than 2” thick, weeds will grow in your mulch. I often hear the argument that “I put mulch down to help keep the weeds down.” This statement can easily be misunderstood and I feel the need to break it down. Mulch can “keep weeds down” in the sense that it will shade out weed seeds in your soil. If you think more mulch the better, I’m sorry to be the bearer of bad news – you happen to be wrong in this case. Weed seeds will grow in the mulch just to spite you. Harsh I know, sorry Dad.
What about perennial weeds? Established perennial weeds are capable of growing through a 2” thick mulch barrier, sure. But also 3” or more as well – think dandelion and the loathed thistle. And by putting more mulch down to suffocate established weeds, you’ll not only have weeds growing through your mulch, but in your mulch to boot! 2. Thick mulch will also create undesirable soil conditions because the plants you’d like to see thriving aren’t receiving enough water AND you’ll be lucky enough to wittiness dog barf fungus. That’s right folks, there is a fungus commonly called dog barf. Any guesses why? This fungus is a tell-tale sign your soil is not receiving enough air circulation. The solution, clear away the mulch. You may need to use a shovel or pitch fork to pierce threw the mulch- it will be pretty compacted.
Okay, so now you know the ideal time to put mulch down, but what kind? There are so many many options. And it does matter what type of landscape you have or intend to have.
Black (triple forever and eternity) This provides great contrast in color in the garden, especially along the front at the bed lines. No matter how well marketed, it will fade in color – eventually. But before it does, depending on the brand, the black dye will dye everything it touches, clothing, hands and usually most upsettingly driveways and walkways. It’s a great mulch to get that clean crisp formal look, unfortunately, not the easiest if you’re the one handling it. With a good hard spring rain, the dye does wash off of hard surfaces.
Brown hardwood – see above rant. Okay, that’s a little harsh…Oakland does have a really nice brown hardwood mulch, that is processed enough that you’re left with a fine texture and rich (more natural looking) brown color. It also achieves a clean, crisp look at the front any garden bed. You can usually catch a good spring sale on the hardwood mulches to get even more for your dollar.
Pine products (bark, nuggets, needles): Naturally dark brownish/red color. Contains no dye and is minimally processed. These types of mulch DO ADD to your soil profile and help to break up the dense clay because this mulch is considered organic matter! As this mulch starts to break down and decompose into your soil, it will add some acidity to your soil. This is great for us central Ohioans because our clay soils tend to be on the alkaline side of the pH scale. Who cares you say? Most ornamental trees and shrubs benefit from a little acid kick, but especially Hydrangeas, Azaleas, Rhododendrons, Mountains Laurels, Pieris, Hollies, Inkberries, Japanese Maples and Crape Myrtles. I also like to use this mulch around my perennials as well for similar reasons. Unfortunately, you’re paying for the added benefits, I general, pine products are going to be a little pricier than most hardwood mulches.
Leaf Mold/Compost – This mulch is ground up leaves that are slightly decomposed and therefore a nice rich dark brown color. This mulch is great in adding organic matter to your soil profile. Often you’ll see this product with added compost- which adds a little more nutrient bang for your buck. It also tends to be organic and therefore safe (and great!) around your vegetables and herbs. (psst..it is often the cheapest when you can find it in bulk).
Okay, phew…congratulations! You’ve made it through the mulch soap box. And it was a big one. But one last thing- you don’t have to mulch every year! What???? Mind blowing, right? But I’m totally for real. If you happened to have put on the mulch a little thick last year or its still 2” thick in areas, simply turn the mulch (grab a small pitch fork or pronged tool) and rough up or as experts say, “fluff” your mulch. And you’ll be all set.
written by Kate Wilson