Friday Rookie Topics VIII: Mulch

Anybody who has a garden can benefit from mulch, and you’ll often see it talked about here on the SFG forum.

So what is mulch? Simply put, mulch is any type of material that is either spread or laid over the surface of your Mel’s Mix as a covering. There are many materials you can use to cover your mix. Here’s a list of common ones you’ll see talked about:

Organic Mulch		Synthetic and Inorganic Mulch
Bark, Shredded or Chipped		Clear, Black or Colored Plastic
Compost		Landscape Fabric
Composted Manure		Stone/Gravel
Grass Clippings		Carpet Remnants
Newspaper
Shredded Leaves
Straw

Notice compost makes the list of organic mulches. Since composts makes up 1/3^rd of our Mel’s Mix, I want to make sure this doesn’t confuse anyone. The difference between compost being part of your mix and compost being used a mulch is in how it’s applied – either worked into your mix to replenish nutrients between plantings, or spread atop your mix as a cover. Keep in mind that all of the organic mulches are things that will eventually decompose and therefore also become compost. But for SFG purposes they can be spread atop our mix as a cover, and then removed when needed. So why would you want to cover up your Mel’s Mix? Well here are a few reasons:

1. To keep your mix from drying out so quickly.
A layer of mulch can protect your mix from the drying effects of the sun and wind, and keep you from getting that crusty layer on the top. Lessened evaporation will help you maintain moisture conditions more evenly throughout your mix.

2. To modify the temperature of your mix.
Different mulches can have different effects on the temperature of your mix. Many of the synthetic choices are used specifically for the purpose of warming your mix up, soaking in the sun either to get your SFG ready for germinating seeds (black plastic, for instance) or for heat loving crops (like the red plastic you’ll see advertised for tomato growing). Conversely, a thick layer of organic material can act as insulation from the sun, which helps to keep your mix cool.

3. To prevent backsplash.
Rain, or watering from above, can cause your mix to splash up onto leaves and fruit/veggies. A clean layer of mulch like shredded bark or straw can prevent this, leaving your harvest cleaner and helping to prevent the spread of disease if there were any present.

Of course, there can be drawbacks to mulch. Introduction of weeds is the most common, especially if using grass or hay, and the lighter weight mulches can also be blown about.

If you desire any of the above benefits of mulching, there are only a few more things you need to know. Spread organic mulches about 1 to 1 ½” thick in your SFG. You also want to mulch only after seedlings have germinated unless you leave holes for the seedlings to emerge (you don’t want a layer of mulch to change the depth of your plantings). And know your soil temperatures and your goal for mulching. Make sure for instance, if you live in a cooler climate, not to lay a nice insulating layer of mulch down until after your soil has warmed up in the spring.

Don’t forget that not all squares are created equal and you don’t have to mulch your entire SFG. A broccoli may have such large leaves that it shades the mix in its own square. Two squares over, a single stem tomato being trained up a trellis may need some protection.

Something to keep in mind – if you are buying something labeled “mulch” make sure the label states that it is safe for vegetable gardens. Though we aren’t applying mulch for the purpose of improving the fertility of our mix, we don’t want to contaminate our mix either and watering will leach whatever is in the mulch into our SFG’s. On the other hand, you don’t need to worry about mulches withdrawing nutrients from your SFG as they decompose. Bark is known to use nitrogen as it breaks down, but we won’t be letting it break down within our mix and it will be removed as a covering between plantings and can be added to the compost pile at the first sign of decomposition.

Great post, thanks very much.

This is a very good article. I mulch, but being in Maine, I usually wait until the ground has warmed up and the warm-weather plants are growing nicely before covering the soil. I'm glad you covered that aspect for newbies.

This is a good rookie topic, I don't usually mulch but I have two rock garden filled with topsoil that I planted my herbs and some flowers in that I would like to mulch. The topsoil doesn't look very nice and the water splashes up onto the herbs really badly and makes them more difficult to wash.

I haven't ever read the bags of mulch, just walked by them but does anybody know if the red and brown (I think cedar) mulch is it dyed or just the color of the wood? I realize there are many different brands but I am also assuming they are made basically the same way.

thanks gwennifer.
Good article.
Quilt bea, some mulches warm the soil, .... like the plastics.
Good to know that others cool it down.

Great topic for rookies, I had been gardening for years before I fully understood what mulch meant.

Most bark mulches I've seen have been dyed and are not natural.

Also, I got some red cedar mulch for the flower beds one year and had the worst time with weed seeds growing up from it. I thought I was safe with more expensive cedar mulch because the year before I just bought some brown mulch and had weed probs, too. Anyway, it was horrid. Now I mulch with straw instead and its much better.

cheyannarach wrote:.. does anybody know if the red and brown (I think cedar) mulch is it dyed or just the color of the wood?

My experience is that you can get colored or no color, although the colored type seems to be more common.

Last spring I bought different colored (shredded cedar wood, not bark) mulch and also natural cedar mulch. I used the colored mulch under some trees, and spread it with barehands since it was supposedly safe. Let me tell you, my hands we so stained with the color it took a lot of scrubing to get clean. What a dumb mistake on my behalf. i also noticed that the water which was in the bags (from rain or whatnot) had picked up quite a bit of the color. I decided I would never used colored mulch again. The natural uncolored mulch looks just fine to me. Besides, the colored mulch from last year now looks awful with the color moslty faded out(meaning washed out of the wood and into the soil!).

How many of you use shredded cedar mulch on their SFG? I have two bags (natural, no color), I'm thinking of using it. I've never used mulch in the garden and my concenr is being able to guage the soil moisture with that layer of mulch in the way.

Anyone use coconut-shell mulch?

Thanks J for the info, I had a feeling but thought it still worth asking, I will stick to the natural wood!

Thanks for putting together another great rookie topic for us gwennifer

I mulch! I prefer incompletely decayed compost, as I can just turn it under in the Autumn. Shredded bark mulch is my second go to for covering growing area, mainly because it clings to itself and is relatively easy to lift if I need to do that. Wood chips of any kind for pathways only.

This year I experimented with mulching my vegetables for the first time. I used finely shredded bark around my tomatoes. It has worked very well so far, kept the soil moist, kept weeds from germinating, and looks very nice. I also used shredded leaves on my summer squash. The leaves have helped retain moisture but - the leaves do not allow water to reach the soil. We had 1-1/2 inches of rain one day and the top 1/2 inch of leaves were wet but down below the 1/2 inch was completely dry. No water reached the soil. Therefore, next year I will not use leaves unless I install a drip irrigation system between the leaves and the soil.

I am installing drip irrigation and plan to mulch with compost or straw.
If I lay the drip lines on top of the mulch will it prevent the MM from getting proper water?
or if I place drip lines directly on top of MM below the mulch, will it cause the drip lines to clog or not work?
Any recommendations?

P.S. using drip lines from Drip Works if that makes any difference.

Place the drip lines under your mulch.
One of your goals here is to prevent evaporation.

Thanks Rooster!