PatArizona

G'day again Lou...

You mentioned "...I have noticed compacting soil and root rot...".

"Root Rot" can kill your bonsai...

Following is some information that might be helpful...


Introduction

Here is a very brief, generic treatment that should help you identify, treat and protect against root rot.

Root Rot? What’s that?

Root rot is a generic term which describes roots that have died and rotted. It is caused by fungi that enter damaged or wounded roots. Some actions/conditions that can invite root rot are:
·Routine, but unseasonal, root pruning;
·Compacted and/or poor draining soil mixes;
·Over or under watering; and,
·High pot temperatures.

Almost any woody plant is susceptible to root rot, however, some of the favorite targets are, Yews, Cypress, Box, Apples, Acers, Beech, Azaleas and Limes.

Are any of Your Bonsai Suffering From Root Rot?

If root rot has developed, you may see rapid wilting, the dying leaves turning dark and clinging to the stem; also, if your conifers have unusually dull foliage, or, generally any plant has smaller, yellow or sparser than normal foliage, and branches dying back for no apparent reason, root rot may be present. If the fungus is not eradicated, it will generally kill the plant.

Affected roots are soon rotted by other micro-organisms naturally occurring in the soil. The disease is then encouraged by poorly drained, waterlogged soils, wet and warm weather.

How can You Control/Avoid Root Rot?

A very free-draining open soil mix (maybe even with no organic matter) will make life very difficult for fungal spores. Remember that there no way to reliably protect against root rot, other than to keep your trees are very healthy, use a fast draining soil mix. And, overwatering (particularly after root pruning) and a poor draining bonsai soil mix will provide access points for infection, and provide ideal conditions for the spores to grow. So, provide your bonsai with gritty, free-draining soil and avoid over watering.

Here is a Rather Generic Process for Treating Root Rot.

First, remove your bonsai from the pot, then try this:

If the roots are black and smelly, it is undoubtedly root rot. If so, rake out the roots with a root rake or a chop stick;

• Wash ALL of the old soil off your tree's roots, including all the black, rotten roots;
• Cut back on the black roots until you reach white cores;
• Discard the old soil and trimmings;
• Soak the root ball in a fungicide solution (follow directions on the label) for at least 10 minutes;
• Clean the pot using a fungicide or disinfectant (preferably both);
• Clean your tools and work area before continuing;
• Repot the bonsai in a fresh, fast draining soil…acoarse-grained soil like gravel and pine bark or pumice and pine bark (or even pumice with no organic component); and,
• Water thoroughly with a root stimulant solution (KLN, Roots2, Superthrive)...following directions on the label.

Aftercare:

• Place your bonsai where it will be protected from the wind, but with as much filtered sun as possible;
• Monitor water content of the soil...let the soil almost dry out before watering (ie., if the soil is bone dry, water yesterday), and water only when water is needed;
• For the next three weeks or so…EVERY TIME YOU WATER…water thoroughly using a root stimulant solution (KLN, Roots2, Superthrive)...following directions on the label;
• Keep the bonsai in partial shade or indirect sunlight for at least 10-12 days…in 2-3 weeks you should know whether or not this was successful; and,
• Then gradually, across 3-4 days, reintroduce the bonsai to normal sun light.

Again Lou...good luck.

Pat

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BONSAI isn't about surviving in a storm, rather, how to dance in the rain.
THE ONLY WAY: Always remember, and don't ever forget, that whatever you read here is not cast in concrete... the intent of any advice is to help. In no way should you feel that I’m saying that my way is the only way…heaven forbid! I've seen far too much of the "my way or the highway" attitude in bonsai as well as in other areas of life.