Growing Desert Cactus

Vinegar may be used on cactus and succulent plants on the condition that, in most cases, the product is rinsed off of these plants very very soon after it is applied. Vinegar left to dry on these plants can cause cosmetic damage to skin or worse cause enough damage to leaves, stems or the root systems to open the door to death by fungal infection.

The vinegar we've tried is intended for use in cooking which, in most cases, is a weaker acid than horticulture vinegar. For our tests vinegar was sprayed of several varieties in an amount that would completely cover the plants in 2 applications given 2 weeks apart in time. We have no interest in testing horticulture vinegar, because the vinegar for cooking proved to be strong enough to show results both harmful and with some benefits.

In some cases the damage caused by vinegar only left scares, but in others the applications created conditions for fungus to attack these plants. Some plants such as Aloe, Haworthia and Euphorbia suffered small amounts of cosmetic skin damage. Other plants sprayed in the same manner such as Hurenia, Echinocereus, Mammillaria and Rebutia suffered fatal results. The plants which died from the applications of vinegar were done in by fungal infections anywhere from 2 weeks to 3 months after the second application of vinegar. It is important to keep in mind that cactus plants often appear healthy for several months after they have been fatally damaged. All of the plants we subjected to 2 spray applications of vinegar suffered some kind of damage if the vinegar was left to dry on the plants.

Beneficial Uses of Vinegar on Cacti and Succulents - 4 Different Kinds.

1. Removing hard water stains from cactus and succulent plants:

Two things have to be done for this to work with the minimum risk of harming the plants; first remove the plants from their soil and second rinse the vinegar off of the plants very very soon after the application. Spraying vinegar on a potted plant and letting the fluid run into the soil can, in some cases, lead to the death of the plant. Working with the plant removed from its soil will keep the vinegar from soaking into the roots and minimize the potential for root damage. The Ferocactus pictured above has the kind of hard water stains that typically build up on plants watered frequently with tap water.

This plant was unpotted, sprayed with vinegar for about a 30 second exposure and then all of the vinegar was rinsed off under running water. The vinegar dissolved the hard water stains and the cactus was repotted a few days later. In general it is a good idea to dry cactus plants out, in bare root form, for a few days before repotting them. A good location for this drying out period is in a northern window where they will receive indirect sun. Any time a cactus is being potted or repotted it is better to keep the roots dry and, as it was in this case the entire plant was left to dry for a few days before being repotted. This Ferocactus is now free of hard water deposits and is being watered with rain water to prevent the development of new hard water stains.

2. Vinegar as a solvent for removing insects:

It is almost impossible to make a recommendation for using vinegar for insect control, however horticultural vinegar may be a different matter, and we are ignoring this kind of product. We only tried vinegar for cooking as an insect removal solvent, and generally it is less effective than alcohol based products, or for that matter products designed to control insects like commercial insecticides.

Insects have water resistant surfaces which provide protection for them in nature. It appears to be the case that removing insects with vinegar is almost as effective as using plain water because of the animal's ability to repel water. In an attempt to remove some mealy bugs from a Hurenia the vinegar would be repelled and the insects had to be scrubbed off with more force than if a solution of soapy water had been used.

Perhaps enough exposure to vinegar would be toxic to insects and there may be some insects which can be easily destroyed by vinegar, but keep in mind that the cactus or succulent plants may also be harmed by the vinegar.

3. Vinegar as an agent for controlling surface fungus on plants:

Note: Vinegar applied to broad leaf plants with surface mold will often cause the plant to drop the leaf. This is also the case for succulents which produce thin leaf structures like Euphorbia milii (Crown of Thorns).

Usually if a cactus or succulent plants have fungal infections the plants are simply going to die, but with surface mold the plants will have some skin damage but survive. We applied vinegar (of a strength intended for use in cooking) to a Crassula argentea (Jade Plant) and an Euphorbia meloformis with good results. The application of vinegar arrested the spread of the mold with one very light spray application only to the locations where the mold was attacking the plants. These plants retained scars on their skin where the vinegar was applied, and they would certainly have scars from the mold no matter how this mold had been treated.

4. Using vinegar to stop mold from destroying cactus seedlings.

Vinegar has been very useful for us in stopping some kinds of mold when germinating seeds. There are many kinds of mold that can become problems when growing cactus and succulent plants from seed, and usually it is only a matter of removing some decaying organic matter. Often a seed which fails to germinate will turn into a fuzzy ball of mold and removing this small mass of fungus from the seed medium will be the end of this kind of mold problem.

There are also problems with mold caused by Sciara flies laying eggs in medium for germinating cactus seeds, and vinegar is unlikely to do much in the way of helping to stop this problem. More information on Sciara flies and cactus seed starting?

The kind of mold vinegar has proved itself to be effective in stopping is a long slender structured mold that rapidly grows across the surface of the soil. This kind of mold growth is very destructive to seedlings and can wipe out an entire seed tray in less than a week if allowed to grow unchecked. In repeated trials a very gentle misting of vinegar on this kind of mold has stopped it, and saved hundreds of newly emerging cactus seedlings. The applications were a gentle mist applied with a spray bottle only one time, and the vinegar also landed on newly emerging seedlings too. The seedlings have always survived the vinegar application, but it is surely the case that too much vinegar would harm cactus seedlings too. With this kind of mold, which is very fatal to seedlings, it is well worth the risk to apply a small amount of vinegar to the mold and seedlings in order to stop the mold.

# posted by Adv. Blogger @ 10:13 AM