Al, advice about hydrogen peroxide, foliage pro, gritty mix

rubyjchangApril 8, 2012

Hi Al and everyone,

I have recently transplanted all my plants into the Gritty Mix (about 3 month ago). It seems that they are all doing great! Especially my michelia alba, last month so many new growth were seen! However...recently it seems to be doing not so great, young leaves drop before they open, I pried a little bit of the gritty mix open and found that there is little bits of roots are brown (not mushy though?)...I hope it is not root rot! Doesn't old roots sometimes die? Especially if they are in the top layer of the Gritty Mix (which dries out sometimes?) The plant seems happy except the dropping of young leaves (but sometimes root rot plants appear healthy until it is extensive). I am furstrated because I thought I did so great with my first try at the Gritty Mix! I know Gritty Mix is wonderful!...

I have also been reading one of your post which stated that hydrogen peroxide if used in concentration of 1oz to a quart could help aerate the root. I know that the Gritty Mix is very very porous and great for aerating roots already. But more aeration couldn't hurt right? So to use hydrogen peroxide, I have a couple of questions.

1) Can you use hydrogen peroxide and foliage pro together when watering? Will the oxidizing effect affect the fertilizer?

2) If I use hydrogen peroxide every other week, will that negatively effect my plants? Since it is an unstable condition where the roots get oxygen one week and the next week not? (since peroxide decompose in 3-4 days). will that stress the plant, and instead foster bacteria growth? I really don't want the opposite effect.

3) Will using hydrogen peroxide cause a dependence of my plant? Where if I skipped hydrogen peroxide application for a month, and my plants do even worse?

Sorry for all that question! I greatly appreciate any feedback!

Thank you!


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I have a question for you if I may?

Why do you even want to use it if the mixes you are using are providing good aeration in the first place? There is no need for it in the gritty mix.


    Bookmark   April 8, 2012 at 4:02PM
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I really like the Gritty Mix for the great aeration. The problem is when I am worried about "my" particular Gritty Mix. This is the first time I tried the Gritty Mix, and I cannot guanrantee that it is made to the perfection to Al's instructions (I tried really really hard though).

I would like to use H2O2 as a preventative to root problems or provide my plants with the added oxygen in case that my gritty mix is not as functioning properly as possible.

Also, my michelia alba, I don't know, I am really worried for it, it doesn't seem to happy all of the sudden. Any advice?

Thank you,

    Bookmark   April 8, 2012 at 5:28PM
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tapla (mid-MI z5b-6a)

FWIW - I wrote & posted this about using H2O2 in containers a number of years ago and several times since.

H2O2 has an extra O atom (compared to H2O) in an unstable arrangement. It's the extra atom that makes it useful in horticultural applications. Generally, we're not concerned with aerobic forms of bacteria normally occurring in container media or on roots. Since H2O2 is an unstable molecule, it breaks down easily. When it does, a single O- atom and a molecule of water is released. This O- atom is extremely reactive and will quickly attach itself to either another O- atom forming stable O2, or attack the nearest organic molecule.

Reduced O levels and high temperatures encourage both anaerobic bacteria and fungi. Many disease causing organisms and spores are killed by O, and the free O- H2O2 releases is very effective at this. Additionally, when plants growing in water-retentive media are treated with H2O2 it will break down and release O into the area around the roots. This helps stop the O from being depleted in the water filled air soil air spaces until air can get back into them. High O levels at the roots will encourage rapid healthy root growth and discourage unwanted bacteria/fungi.

I know H2O2 comes in several different strengths, the most common of which are 3% and 35% solutions. Least expensive is the 35% product (what I use) which you dilute (to an approximate 3% solution) by mixing 1:11 with water. I have used the 3% solution at 1 to 2 tbsp per gallon as a cutting dip/soak, and have mixed it into irrigation water for plants in extremely water retentive soils at up to 3 tbsp per gallon, both with good results and nothing adverse apparent.

H2O2 in high concentration is a powerful oxidant and quickly oxidizes almost anything it contacts, so be careful with it if you use it. A solution that is too strong can destroy any organic molecule it contacts.

I've seen this chart posted several times as suggested strength solutions for use in watering plants. You may wish to start at a lower concentration , such as I've used, and experiment.


1 cup, add 1-1/2 teaspoons ... 35% - 7 to 10 drops
1 quart, add 2 tablespoons ... 35% - 1/2 teaspoon
1 gallon, add 1/2 cup ... 35% - 2 teaspoons
5 gallons, add 2-1/2 cups ... 35% - 3 tablespoons plus 1 teaspoon
10 gallons, add 5 cups ... 35% - 6 tablespoons plus 2 teaspoons
20 gallons, add 10 cups ... 35% - 3/4 cup plus 1 tablespoon plus 1 teaspoon

1) you can use them together w/no problems, but you shouldn't need it if you're watering correctly & the gritty mix is made even CLOSE to the suggested recipe.

2) Plants are reactive organisms. They will reach favorably to increased O2 in the root zone, and unfavorably to reduced levels. If you use excessive amounts of H2O2, it can kill viable tissues, so don't over use it.

3) Your plants won't get addicted to H2O2 to any greater degree than they are addicted to water.

I would urge you to lift the plant from the pot & take a look at the roots to see what's going on, then prune roots back to sound tissue if you find rot as an issue. At that point, a dunk in a solution of H2O2 or unscented household bleach might be an appropriate measure.


    Bookmark   April 9, 2012 at 9:45AM
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Thank you so much for your help! It really helped!

I am so reluctant to lift the plant out of the has just been doing so well until now. Every time I transplant it/repot it, it has this incredibly slow recovery time...

I guess I am just hoping that the plant is fine because "it seems" to be good except no new growth...I know I should look at the roots...

Al, do plant roots always look white and fleshy (for most plants)? Can there be a tiny proportion of roots that are not? Maybe old roots that are going through their "normal" cycle?

Thank you,

    Bookmark   April 9, 2012 at 6:26PM
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