En EspaŅol

Q. Who is Mr. Smarty Plants?

A: There are those who suspect Wildflower Center volunteers are the culpable and capable culprits. Yet, others think staff members play some, albeit small, role. You can torture us with your plant questions, but we will never reveal the Green Guru's secret identity.

Help us grow by giving to the Plant Database Fund or by becoming a member

Did you know you can access the Native Plant Information Network with your web-enabled smartphone?

Share

Ask Mr. Smarty Plants

Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.

Search Smarty Plants
    
 
See a list of all Smarty Plants questions
Can't find the answer in our existing FAQs, submit a question to Mr. Smarty Plants.
Need help with plant identification, visit the plant identification page.
 
rate this answer
12 ratings

Monday - April 06, 2009

From: Plano, TX
Region: Southwest
Topic: General Botany
Title: Will molasses harm beneficial organisms in my garden?
Answered by: Nina Hawkins

QUESTION:

If I use molasses in the garden, I am hoping this will NOT kill the beneficial nematodes and my earth worms, or other good bugs such as lady bugs? Thanks.

ANSWER:

Boy, your seemingly simple question sure turned out to be a doozy to research!  I am not a soil biologist, so please bear in mind that this is not the answer of an expert, but rather that of a gardener searching for reliable information - just like you!  The short answer is no, using molasses as a soil amendment or foliar spray in your garden should not harm any beneficial organisms living in your garden.  Molasses (both liquid and granular) is a widely accepted organic soil amendment that is used to promote biological activity in the soil by providing a readily available source of food (carbohydrates) to microbes already living in the soil.  One of your local organic gardening experts, Howard Garrett, also recommends spraying a molasses mixture onto garden plants before releasing beneficial insects (lady bugs, green lacewings and trichogramma wasps) to encourage them to stay in your garden and claims that molasses used in the garden repels fire ants.  Maryanne Caruthers-Akin, another organic gardening expert out of Portland, OR, uses molasses in her garden beds to attract earthworms - so no harm there.  The Hawaii Agriculture Resource Center says that molasses soil amendments affect the "soil microbial ecology, usually resulting in lowered populations of plant parasitic nematodes as well as having other favorable effects on plant growth.  The specific mechanisms are not well understood and vary with the crop, soil conditions, and nematode species present."  (Links are listed below.)  I have been completely unable to find any information claiming that the use of molasses will harm beneficial nematodes and it is uncertain just how molasses works to discourage "bad" nematodes.  Perhaps healthier plants are simply a less appealing target.  Whether molasses will improve your soil or not depends on how healthy and biologically active it already is, but, as long as you use it according to the instructions provided on the product, it certainly won't harm the other organisms that call your garden home.  As a side note I'd like to mention that, barring past use of chemicals that may have decreased the natural amount of biological activity in your soil, plants that are native to your area usually do not require any soil amendments to grow and thrive and are actually adapted to living in soils that are less biologically active.

Dear Dirt Doctor by Howard Garrett

Earthworms - Surprising Partners in the Creation of Healthy Soils - Tilth

Molasses Soil Amendment for Crop Improvement and Nematode Management - S. Schenk

 

More General Botany Questions

Starting a sweet potato in water in Duluth MN
April 11, 2011 - I am trying to start a sweet potato plant in water. I noticed 3 days after it's in water, there is white finger like(hairy) areas at the tip of the bottom of the potato and also on the sides. I have...
view the full question and answer

Do plants grow better under artificial or natural light?
May 25, 2009 - Dear Mr. Smarty Plants, So do plants grow better under artificial lights, or sunlight???? and if so what happens when they are growing? Which seedling sprouts first??? What happens as they grow? I a...
view the full question and answer

Flowers for days on end in California
March 30, 2012 - What are some plants or flowers that I can grow "all-year" in California?
view the full question and answer

Are leaf margins of Chilopsis linearis toothed from Austin
December 22, 2013 - Are the leaf margins of Chilopsis linearis, Desert Willow, smooth or toothed? The NPIN descrip says willow-like. Most willows have toothed leaf margins. Thank you.
view the full question and answer

Plants adding calcium to soil
June 08, 2006 - Hi, I am looking for a resource to help determine the functions of native plants. For instance, nitrogen fixing can be found in Indigo, Lead plant, lupines. Are there other plants that add back cal...
view the full question and answer

Smarty Plants's Facebook profile Support the Wildflower Center by Donating Online or Becoming a Member today.

Mr. Smarty Plants wants you to be his Facebook friend. Click the Facebook icon to add yourself to Mr. Smarty Plants list of friends.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | SITEMAP
© 2014 Lady Bird Johnson Wildflower Center