Another blog about mulch? Yep, that’s right. Why? Because we care about you and we care about the plants you take home from Rainbow Gardens. It is our desire to continue to offer you gardening tips that only increase your chances of success. Mulch is one of those products that is always beneficial and especially useful for your plants during summer and winter. Today’s blog talks about what mulch is and how to apply it, and gives you in depth explanations for our reasons for using it. I think you should go ahead and put mulch on your shopping list for your next trip to Rainbow Gardens.

Mulch in hands

Types of Mulch

Mulch can consist of many things and can be organic or inorganic.

Organic Mulch Examples: Leaves, grass clippings, shredded tree bark, hay, organic compost (mix of decayed or decaying organic materials),covercrops, etc…

Inorganic Mulch Examples: Pebbles, gravel or stone, black plastic tarps, rubber mulch, etc…

The focus of this blog is on the benefits of organic mulch. 


Mulching tomato plants

Top 4 Reasons Why You Should Use Mulch Around Your Plants


  1. For Soil Health. This is my number one reason for using mulch. I can’t overstate how important soil health is in regards to the health of your plants and your success with gardening. When you learn that organic mulch breaks down over time and releases  nutrients in the soil that become available for plant uptake, it becomes a no-brainer that this product should ALWAYS be used in your gardens, lawns, and raised beds. Organic mulch and compost offers benefits to the soil such as: mycorrhizae fungi, growth-promoting hormones, nitrogen fixing microorganisms, buffering against chemicals and high/low soil pH, increases activity of beneficial life (earthworms, etc…), continuously releases nutrients over a long period of time.
  2. For Soil Temperature Regulation. As stated before, mulch keeps your soils cooler in the summertime and warmer in the wintertime. This means the roots of your plants tend to be happier and less stressed during these extreme seasonal temperature changes. In a study performed by Malcolm Beck @ Garden Ville mulched soil and non-mulched soil were ultimately tested for temperature during the month of August in Texas, on a 104° day (can I get an “It’s crazy hot then!”?). The soil in the mulched areas (one a pine bark and the other a native mix mulch), had temperature reads of 85° and 84.5° respectively, while the soil in the non-mulched, bare areas was reading an astounding 120°, a 35° difference! Folks, that could mean the difference between a plant that survives through summer and one that doesn’t. 
  3. For Moisture Retention. During this heatwave we are currently experiencing, moisture retention is super important to the vitality of our plants. In extreme weather temperatures, supplemental irrigation is often needed just to have our plants survive. Mulch creates a barrier on top of your soil to help hold in the moisture and prevent rapid evaporation, which especially happens during our summers in San Antonio. This same barrier also protects your plants from soil borne diseases which tend to get splashed up onto the foliage when watering. 
  4. For Weed Prevention. Mulch makes it harder for seeds to get blown and grown. Seeds need contact with the soil and easily sprout when bare soil is plentiful; mulch prevents that. If a seed does find its way to the soil, the weed seedling is also easier to pull out of mulch than out of soil. 
Planting in the garden.

4 Concerns About Using Mulch (Few and not enough to outweigh the benefits.) 

  1. Planting once mulch has already been applied. If you choose inorganic mulch you’ll need to pull the mulch back to reveal the soil. Plant your chosen transplant and then pull the mulch back around it. 
  2. Mulching new spring vegetables too early. This actually could impede their growth by making the soil cooler rather than the warmer soil these veggies need. Wait for about ….. of growth and then mulch.
  3. Periods of heavy rain: Although in general we don’t experience this much in San Antonio, there are times when the rain doesn’t let up for a while. This is when following the advice for the correct amount of mulch to apply comes in handy. You can also pull back the mulch from the roots of your plants until the rains subsides if you’re concerned. Too much wet weather and a  heavy application of mulch could cause root rot and fungal issues. 
  4. Piling mulch against the trunk of your tree. This is a no-no. Start applying mulch/compost about a foot out from your tree trunk and extend it past the dripline (where the canopy ends) of the tree by about a foot.
Rainbow Gardens carries mulch products in bags that are easily loaded up your vehicles and convenient to carry to your garden spaces. We have a variety of types of mulch to choose from so come on in and protect your plants through this summer and the future winter!


~The Happy Gardener, Lisa Mulroy