Foliar Spraying and Drenching

Foliar spraying and drenching small spayer

Foliar spraying and drenching are my favorite methods for applying compost tea to my garden, landscape, and house plants. These methods can also be used with any number of commercially available products as well.

I get a few questions when I mention foliar spraying with compost tea, mostly in the vein of “If you are so big on feeding the soil and not the plant, why are you always recommending foliar spray?”  It is a legitimate question.

Nutrient Absorption

For many years, it was believed that plants’ only source of nutrients was through absorption at the root level.  In 1844 a set of experiments proved that not only could plants lose nutrients through their leaves by rain, they could also absorb nutrients through their foliage.  Foliar spraying became a thing.

Yes, feeding the soil is the whole basis of my organic program.  However, foliar spraying is not necessarily contrary to that program.  There are ways to incorporate foliar spraying and feeding that will significantly help the plants and stimulate the natural processes in the soil to increase soil health.

Foliar spraying makes micronutrients immediately available to the plant and you can often see nearly immediate results.  Foliar spraying is not a substitute for healthy soil, but it is a way to give plants a boost during times of high stress.

Some Points to Remember

foliar spraying and drenching woman spraying
  1.  Less is usually more.  Light regular applications are generally better than infrequent heavy applications.  Mists are better than big drops unless you are trying to control pests.  There is some logic to applying heavy sprays and allowing the excess to drip from the plants onto the soil.  In my opinion, you are better off applying a light spray and then doing a separate drench of the soil.
  2. High humidity increases foliar absorption.  Try to spray when the air humidity is highest.  Early mornings or late evenings are usually better and will result in greater absorption by the plants. During the heat of the day, the stomata (small openings in the plants leaves) close to prevent the plant from losing moisture.  My recommendations are to spray for feeding purposes in the early morning.  Spraying to control pests should be done in the late afternoon. 
  3. Young plants respond better to foliar feeding than mature plants. 
  4. Adding a bit of molasses to your spray will encourage the growth of beneficial bacteria on plant surfaces.  This can help with nutrient absorption and help plant responses and defenses against pathogens and pests.
  5. Foliar feeding strengthens plants and helps them tolerate extremes in heat and cold better.
  6. Foliar feeding should not be used alone or as a substitute for your regular soil program.  You should continue to follow the organic program for soil building and feeding.  Foliar feeding is a supplement, not a substitute.

Drenching

foliar spraying and drenching watering can

The same formulas that are used for foliar feeding can be used for drenching your soil.  If your compost tea is prepared correctly, not only are you delivering a nutrient-rich product to the soil, you are inoculating your soil with beneficial microorganisms that will continue to grow and multiply, further enriching your soil biome.

Recipes

Several commercial products are suitable for foliar spraying and drenching.  Garrett Juice and Bio S.I. are the two easiest to find.  However, you can make your version of these products easily and economically at home.

The basis for both products is compost tea.  You can find more information on compost tea in our article here

When making compost tea at home, remember that you will need to strain the tea carefully before using it in your sprayer to prevent small debris from clogging the spray tip. 

We dilute our compost tea for foliar spraying by mixing two cups of full strength compost tea to one gallon of water and then spray immediately.  The same dilution rate is used no matter what we are spraying.  We spray everything in our landscape, even our turf.

The compost tea can be used full strength or diluted as a drench.  It doesn’t matter.  The great thing about using these organic-based fertilizers is that it is almost impossible to damage your plants by overfeeding.

Links and Resources

For more information about organic gardening, lifestyles, and living, visit our website at West Texas Organic Gardening.

If you found the information here helpful, you might also find these articles on our website of interest.

Molasses

The Vinegar Question

Feed the Soil

If you have more specific questions or problems, you can contact us using the contact form on our website. You can also post your question to our community forum at this page; West Texas Organic Gardening Community Forum.

We have a Facebook page and love your comments, questions, or input. You can find us on Facebook using this tag. @westtexasorganicgardening

Check out these items on Amazon that might help you with your gardening projects.