Worms Castings & Teas – Drought Tolerance in Plants (Revisited)

Last week I posted an update for my castings/tea alfalfa growth experiment (including a video showing the results). A short time after that I really started feeling like it was time to wrap things up. It’s been interesting for sure – but I’m keen to use my warming mat and grow lamp to start some new plants (perhaps edible this time – lol).

But there was one thing I wanted to try first!

Some years ago now, I “accidentally” discovered that castings seem to have the potential to improve drought resistance in plants – even when added in very small amounts (we’ll come back to this further down).

I thought it might be interesting to see what would happen if I simply stopped watering my treatments altogether. So that’s exactly what I did. I honestly don’t know the exact day I last watered them, but I will simply assume it was the same day I filmed my update (Feb 27th).

Keep in mind these are pretty small pots with a warming mat down below (layers of newsprint and a tray moderate the warmth somewhat, though) and a small double grow lamp directly above – so it didn’t take all that long for the soil to dry out and for water stress to start taking a toll.

Of course, the first casualty was the liquid fertilizer treatment – which was already in pitiful shape by my last update. It is safe to say those plants were completely dead by Mar 1. As you can see below, the water-only treatment was still hanging in there, but not looking nearly as good as the tea and castings treatments.

By this morning (Mar 3) the water-only treatment was really looking rough, and even the castings treatment was clearly suffering…yet for some reason the tea treatment was still going strong (those green leaves you see in the liquid fertilizer pot are actually hanging over from the tea treatment – lol).

Rather than simply waiting until all the plants died off, I decided to see what would happen if I re-hydrated the soil in all the treatments. Apart from not wanting to feel too cruel (lol), seeing how well the plants bounc back will also be interesting. Plus, I would also like to check on root growth in the pots – which will be easier once the plants are hydrated.

Getting back to my “accidental” discovery – amazingly more than 12 years ago as I type this…

I was experimenting with some chia seeds – curious to see if castings would positively impact germination and early growth. I let two batches of seeds soak overnight – one in plain water, one in water with literally a pinch of castings in it.

What’s really interesting is that the early results mirrored those of the alfalfa experiment fairly closely – with nothing too earth-shattering happening during the first stages of growth. In fact, the water treatment seeds seem to germinate earlier overall, and those seedlings started growing more vigorously.

But then things started shifting in favor of the seedlings treated with (once again, a very small amount of) castings.

Me being me, I ended up side-tracked and forgot to water them for a while. When I finally checked on them, the water-only seedlings were in terrible shape while the castings-treated seedlings were looking much better.

Just to be sure it wasn’t a fluke, I watered them then neglected them completely again…same results.

Here is an image from that original blog post (“Worm Castings and Drought Resistance“):

The fact that only a tiny amount of castings was needed last time, and that it is the liquid castings extract treatment dominating this time around seems to suggest there is something in the castings that’s responsible for the boost in drought-tolerance.

I will aim for another update later in the week to show how the plants have bounced back (or not) after re-hydration.
Stay tuned!

** UPDATE March 10th **

Here is a video I recorded (Mar 5th) showing how the plants looked after rehydration:

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    • Steve
    • March 8, 2020

    I’d wager the humic properties of the worm castings is one property that greatly enhances plant survival rates. This was clearly demonstrated to me, while working in my garden plot, during a dry spell. A small tomato single seedling root was clinging to a remnant of worm castings material distributed from my bin. By all accounts that tomato should have been dead and shriveled. Instead it looked healthy and vigorous. There’s some powerful magic in those worm castings.

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