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  • Hydrophobic Potting Soil

    Here is an article I found about hdrophobic potting soil. This may be of interest especially for those who may
    be just starting out.
    Watering Hydrophobic Soil

    Many potting soils become hydrophobic—tending to repel water—when they dry out, and are difficult to re-wet. Gardeners may see water draining out the bottom of a pot and assume that means that the soil is saturated. But the water might be running between the side of the pot and the hydrophobic root ball instead, barely wetting the outer surface and leaving the center of the root ball dead dry. Small seedlings from nurseries are particularly prone to this, especially if they have become rootbound. It can happen to large container plants as well.

    Potting soils often contains peat moss which is valued because it decomposes slowly, is lightweight, and retains water. Paradoxically though, when peat moss dries out it is very difficult to re-wet. Bags of potting soil can even dry out in storage.
    Rehydrating soil

    Simply watering hydrophobic soil as usual is unlikely to rehydrate the soil since it resists re-wetting. Here are four effective techniques for rehydrating a pot of hydrophobic soil:
    1. Submerge the whole pot in a bucket of water. This is drastic but fast. Initially there will be so much air in the root ball that the pot will float. When holding it under water, you will see the air bubbles escaping as the air is displaced by water. Remove the pot once the bubbling stops.
    2. Set the pot in a shallow container of water (if size allows), allowing the soil to slowly absorb the water. This technique is known as bottom watering. It may take an hour or more to thoroughly re-wet the soil. Be careful not to leave pots soaking in standing water continuously. Check them after an hour or two and remove them when they are hydrated.
    3. For large containers that can’t be lifted easily, you will need to trickle water onto the soil slowly enough that the water has time to absorb instead of running off. If using a hose on a very slow trickle, be sure to set a timer so you don’t forget about it.
    4. If rain is forecast, you can let the rain do the work for you.


    Notice that just as a full glass of water weighs more than an empty glass, a well-watered pot will be heavier than a dried out one. Get to know how heavy a well-watered pot should feel.
    Other hydrophobic examples

    Hard-packed clay soils and even garden soils can become crusted and resist wetting, letting water run off instead of absorbing it. To re-wet, repeatedly sprinkle the surface lightly, making sure there is no run off. Covering the surface with a mulch such as straw, leaves, wood chips, or compost will also help. Eventually the soil will become moist enough to break up. A gentle, steady rain will also do the trick.
    Coffee grounds make an excellent mulch and compost ingredient. But if firmly packed nuggets of fine espresso grounds dry out, they can become hydrophobic. Take care to break them up, especially if using directly as mulch.

    newnandawg 7b Newnan, GA

  • #2
    Nice addition.
    Calvin, Wish list is to finish working on the new house, someday.
    Bored? Grab a rake, paint roller, or a cordless drill and come over!


    • #3
      Add a squirt of hand soap as wetting agent to the water and the peat moss will quickly rehydrate.


      • #4
        I was thinking of surfactants like a detergent as ThaiFigs states.

        Maxximize Your Available Water! WATERMAXX 2 helps growers use water more efficiently and maintain crop productivity by improving the way water moves through soils.

        NE GA ,Zone 7b Low Temperature of 4F in 2015,17F in 2016,17F in 2017,6F in 2018,17F in 2019


        • #5
          Liquid dishwashing soap will also work.


          • #6
            A lot of people use Dr. Bronners Sal's suds as a natural surfactant. Lasts a long time.

            May the Figs be with you!


            • #7
              Dr Bonners makes great natural products


              • #8
                great post and comments learn something every day on this forum. especially the part about water running out the bottom and thinking you have completed your chore


                • #9
                  I like bottom watering by having a tray underneath the pots. I don't have this problem anymore.


                  • #10
                    Thanks for sharing this info, its good to know... I've used the pot submersion method to quickly re-hydrate hydrophobic containers.

                    Lately I've added a small portion (~ 15%) of Calcined Clay (Turface , Calcined Fullers Earth, etc) to my potting mix which has eliminated concerns about the containers becoming hydrophobic.
                    Pete R - Hudson Valley, NY - zone 5b


                    • #11
                      Using warm water will help, also. The warmer the water the less work to rehydrate.
                      Bob C.
                      Kansas City, MO Z6


                      • #12

                        Originally posted by Harborseal View Post
                        The warmer the water the less work to rehydrate.

                        Thanks Bob, but my dog doesn't need any more encouragement as to why he needs to water the trees...
                        CA 9b "May you sit under your own fig tree..." This metaphor, in use since Solomon, is a wish for the receiver's spirit to know peace, for their family to be secure, and for their life to be fruitful.


                        • Harborseal
                          Harborseal commented
                          Editing a comment
                          Great source of NPK and other minerals.

                      • #13
                        Dawn dish soap, small qty. I store my Peat Moss for year in a air tight barrel (for Fungus Gnats) and re hydrating can be a problem without a "Water Wetter"
                        Wish List - Any LSU fig