Making an outdoors wick-watering system for tropical plants

Question

I'm considering a wick-watering system for few plants which need more water than the plants I have in the same area. The location is shaded, and the plants are on shelves.

Types of pants - Begonias; Don't own any yet, I'm considering adding them to my collection.

Climate - Mediterranean, zone 11. Summer is dry (no rain) but the air is humid.

Potting mix - Mostly peat. Other ingredients (perlite, vermiculite, pumice, etc) may be added if you recommend it.

Watering system - A water tray sits under the planter. The planter is above the water line, so that the drainage holes never touch the water. An overflow outlet will not allow the drainage holes to submerge even after a heavy rain. The only way the water reaches the planter is via a wick that comes out through the drainage holes down to the bottom of the tray.

Water quality - I have access to ample source of A/C water runoff, so that water does not contain any salts which may accumulate. Liquid fertilizers are added to the water that fills the trays.

Quality - All components are standard, i.e. I will use planters, not old buckets. Wicks will be made out of ropes, not old rags, A tray will be flat at the top, so that the planter will fit right on top of it, leaving no gaps. An overflow outlet will be the only outlet for water drainage, mostly for rain water

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How well, or how bad, will my watering system perform given the following:

• Rope material: I'm intending to use a non-degradable material. Which material, and which filament size I should use for a good capilary action? Is rock-wool a good choice, and if so, are there rock-wool ropes on the market?
• How wet will the potting mix become, assuming the water in the tray has not yet been used-up? Will I have soggy conditions, moist and aerated soil, or water barely reaching the bottom of the planter?
• Is a standard potting mix suitable for such use? Should I amend the mix with other ingredients, like Perlite, pumice or Vermiculite?

Answer 1

Q Which material, and which filament size I should use for a good capillary action?

A Rockwool I have seen is a loose fibre and unsuitable as a wick. A Google search for capillary mat will show you numerous sources where you can get large sheets that can be cut into strips up to an inch wide and inserted into the root ball with a knitting needle if you are using an individual reservoir for each plant.

Q How wet will the potting mix become, assuming the water in the tray has not yet been used-up?

A As long as the reservoir does not dry out causing the soil to dry out the soil will be moist near the roots and dry near the top. If the soil dries out it will need to be watered from the top to re-establish a chain of water molecules that can move from the reservoir to the roots

Q Is a standard potting mix suitable for such use?

A Yes, no problems or need to add anything

Depending on the type of water you have you may find the wick will get crusty with dissolved salts. Replacing the wicks yearly with new and then washing the old wick in vinegar is a good idea.