Mulching Raised Beds: How to use mulch as a weed barrier and to maintain mositure

Mulching is an essential part in the well-being of every garden, but especially crucial for success in raised beds.  There are many articles on how to build, grow and what to plant, but mulching seems to be a lighter topic.

Close to 80 percent of my farm’s gardens are raised beds and mulching is one of the main keys to successful crop production. Raised beds have many pros, but also a couple cons- the main one being they must be watered consistently.

This is one of my farms raised bed gardens. You can see the mulch over the beds

This is one of my farm’s raised-bed gardens. You can see the mulch over the beds

Mulching serves a two-fold purpose:

  • To aid in maintaining moisture in the beds.
  • To act as a weed barrier.

Here are some tips on how-to use mulch as a weed barrier and to maintain moisture in your raised beds:

What should I use to mulch?
~Grass clippings or straw are what I recommend. I prefer grass clippings because after a few times of watering and/or rain, the grass becomes a nice, solid mat.
~Leaves will also work.

How deep should I mulch?
~I recommend 3 to 6 inches deep. This works great for optimal moisture control and weed barrier.DPP_0013

When should I mulch?
~Two factors to consider are: a) are you direct seeding? or b) are you setting out transplants?
~If you are direct seeding, I recommend that you mulch 2 inches deep, leaving about 3  inches on either side of the row where you planted the seeds. You don’t want to bury the seed row with the mulch.  Once the seed’s germinate and the plants grow to a height of 6 inches, then mulch 2  more inches.
~If you’re planting transplants, then mulch up to the bottom leaves on the plants stem.

Do I have to water as often if I mulch?
~Yes! In the hot months of July and August we water about 2-4 hours everyday. Typically plants in raised beds are shallow rooted and raised beds dry out much faster, even when mulched.

What do I do with the mulch at the end of the growing season when I’m cleaning my raised beds out?
~I leave whatever mulch I used. I then put 3 to 6 inches of composted manure on top.  In the spring, I hand rake it into the soil a week before I’m ready to plant.  This acts like a green manure crop for your soil.peppers

No matter what you decide to mulch with, getting your soil checked annually will help you know what it may need in the way of nutrients.

Now I’m off to the gardens,


Jean Smith
Jean Smith is a mother of six, organic farmer and freelance writer dwelling with her family on their five acre farm in the Thumb of Michigan. She is a self professed master gardener with over 15 years experience who loves to write and teach about her passion for and knowledge in organic gardening. You can read more of Jean's writings at her blog, For Dragonflies And Me