Let's Grow Stuff

- Greetings from the garden, and welcome back to Let's Grow Stuff.

My name is Ben, and today we are exploring the wide world of mulch.

So, Let's jump in and get started.

First, let's understand what mulch is and why we use it.

Mulch is an organic material that we apply to the surface of our soil around the base of our plants.

Mulch can have a number of uses, from helping us to conserve soil moisture to changing our soil's fertility or preventing weeds.

Now, the type of mulch we use should vary based upon where and what we're growing.

First, how and how long will it take to decompose?

Second, how and to what degree will it change our soil fertility or pH balance as it decomposes?

Third, where is your mulch coming from?

This question is especially important when it comes to limiting the spread of harmful critters and plants which can travel in mulch.

Let's begin by talking about one of our most common mulches, shredded bark and wood chips.

Shredded bark is a good and affordable option for establishing new plantings.

The smaller the chunks, the faster it will decompose.

For wood chips, they work great as a pathway material because they decompose slowly.

A 2 to 3" layer should last about two to three years.

When using either bark or wood chips around trees and plants, don't mound it up too close to the base of a plant because it can harm them.

This can inhibit air circulation between the atmosphere and our soil, so it's best to apply only what we need for a single season, usually 1 - 2".

Bark mulch and wood chips can change our soil's pH slightly, making it a bit more acidic, but this tends to happen over a long period of time because these materials decompose slowly.

This can be a benefit if you're trying to grow plants which prefer acidic soil like evergreens, rhododendrons, azaleas, and blueberries.

Finally, let's talk sanitation.

It's always a good idea to ask your garden center where your mulch is coming from because it could be carrying a pest like jumping worms.

Jumping worms are a relatively new aggressive pest that changes soil architecture and fertility over time.

They typically enter our gardens via mulch, and your best option for control is to prevent their arrival in the first place.

Next, let's talk about straw mulch.

Straw will decompose quickly, within a single growing season.

It won't significantly change soil fertility or pH, and it's a good choice for veggie garden beds as a weed barrier and water insulator.

If you begin with about 3 - 4" around the base of your plants in spring, it will settle to 1" or less by summer.

When it comes to sanitation, straw is less likely to harbor insects but keep an eye out for new weeds which might have traveled along with it since straw is an agricultural byproduct.

Finally, let's talk about mulches that you can make at home.

Many gardeners use grass clippings for mulching veggie gardens.

Fresh cut grass is high in nitrogen and will stimulate rapid growth of leaves and stems.

It will also break down very quickly and may decompose entirely by the end of the season.

If you have an organic lawn, you also likely have a few dandelions.

Don't use grass clippings when dandelions are going to seed because those seeds may start growing in your garden!

If you have mature trees in your landscape, you can also gather leaves in the fall.

Chopped leaves are one of the best mulches for any garden because they allow air and water to circulate freely and break down quickly, they have a relatively low impact on pH and tend to be weed- and pest-free.

Leaf mulches are also available for purchase, but those might carry pests like jumping worms.

Well, there you have it.

Knowing when and how to use mulch is important because not all mulches are created equal, and there are options we didn't even cover here today.

So keep these three questions in mind as you're evaluating the best choice for your garden.

Now, don't forget there is so much more to learn online at pbswisconsin.org/ letsgrowstuff There, we have more videos, tips, tricks, and a blog to help you grow a better garden.

So, until next time, happy gardening.

- Funding for Let's Grow Stuff is provided by American Transmission Company, Ganshert Nursery & Landscapes, Willy Street Co-op, Focus Fund for Wisconsin Programming, and Friends of PBS Wisconsin.