Vinegar short-term solution to balance soils' alkalinity

Q: Have you ever heard of adding vinegar or citric acid when fertilizing indoor plants in our area? We collect rain water and use it for our indoor plants.

A: Quite a few people do this to lower our water’s alkalinity, but the effect is short-lived. Our tap water carries a lot of calcium and magnesium salts. The acids are neutralized by these and other salts.

You could determine how much acid to add simply by using some pH litmus paper, like they use for swimming pools. You would add small amounts of acid until you see a shift in the pH of your water into the acid range.

The perfect pH is 6.8, which is the pH of the sap of many plants. Let this water/acid mixture sit for 30 minutes or so and check it again. Keep adding small amounts until you see the pH stay steady in that 6.8 pH level; then you can use it for watering.

As long as you stay with the same water source, you would add the same amount of acid each time to arrive at basically the same pH. If you change water sources, then you would have to do it all over again.

However, as soon as you pour this mixture on our soils it will shoot back up again to the alkaline range because of the massive amounts of alkaline types of minerals that reside in our soils. In short, I wouldn’t waste my time doing this unless it helps you sleep better at night.

Adding a big scoop of good compost to your water instead of vinegar will probably do more good. Let the compost steep for a few hours through a porous sock such as old pantyhose. Use it immediately for watering. Put the spent compost around some outdoor plants or in your garden. Good compost is likely to have gnats so don’t apply the spent compost to the soils of indoor plants.

Q: I have a beautiful loquat tree where the leaves have suddenly started to turn yellow and fall off. Most of the fruit also has fallen off. The tree was located in the middle of grass. I had the landscape converted to desert rock in September. At the same time the watering schedule was changed. I suspect it is being underwatered, but before I increase it I want to ask if the cold winter we had here could have caused this yellowing.

A: Thanks for the pictures. It is probably not the cold. In a lawn situation the roots go everywhere and anywhere and usually spread to about 1½ to 2 times the tree’s height away from the trunk.

In drip irrigation we usually place the emitters a foot or so from the trunk. This bypasses about 80 percent of the root system it created when growing in a lawn.

So, yes, it probably is drought, but perhaps not because you are not delivering enough water. It is more likely that most of the tree roots are not receiving water. You can place emitters over a greater area under the canopy of the tree. But I would also reduce the size of the root system.

Try root pruning the tree to reduce the size of the root system so it is closer to the emitters. Keep tree roots contained in the area directly under the canopy. Wet the soil thoroughly under the canopy and vertically slice the roots in a circle all around the tree at the edge of the canopy. This can be done with a sharpened spade.

At the same time, thin the canopy by removing wood. This reduces the tree’s demand for water. A tree that size will probably require 20 to 30 gallons each time you water. With lawn now gone, the tree will actually use more water since the cooling capacity of the lawn has been removed.

Q: I need to get the bulbs of onions (yellow and red) and garlic planted now that it is April. I was thinking of planting them in the semishade of my Texas ranger shrub. The ranger grows along a wall that faces west so this area doesn’t get full sun until about 1 p.m.

A: You have missed the planting season for onion transplants. This would have been in mid-March in our climate.

Onions can be started from seed but onion seed is planted normally in late September to mid-October. Onion seed will germinate in the fall and over winter with periodic waterings. I normally plant onion seeds close together by broadcasting the seeds in a small area and putting about ¼ inch of topdressing and mulch over the top.

In mid-March I “lift” the young onion plants (transplants) with a spading fork for planting in rows that are about 12 inches apart and 4 inches between transplants. Onions are planted in full sun. They will not do well when planted in competition with other landscape plants such as your Texas ranger.

Garlic seeds are not seed at all but are the cloves inside the garlic bulb. The seeds are separated from the bulb and left in the shade to heal over for a few days. They are then planted in a permanent location in the fall, the same time as onion seeds. Garlic is harvested from May through June depending on the variety.

Get ready to start onion and garlic in the fall and plant transplants of onions in midspring.

Q: In my attempt to plant seedlings this year in my 4-by-8 raised bed, I noticed the day after I planted that some pepper plants were decimated by some kind of insect. When I was amending the soil a few weeks before, I noticed some small wormlike critters in the soil. I sprayed a bit of Bt on the soil but it evidently didn’t do anything to help the situation. I was told to use a powder called “milky spore disease” to kill any grubs or grublike insects. Have you ever heard of this product? They said it works and I only have to apply it one time. That sounds too good to be true. This store said they used to carry the product but not any more for reasons unknown. I went to The Home Depot and Lowe’s, but neither store had the product.

Can you advise me on this product and where I might find it or some other solution? I removed the damaged plant and I’m trying to revive it.

A: The milky spore product only works on some types of insects such as Japanese beetle, which we do not have in Southern Nevada, and a few closely related insects. Milky spore is a bacterium and works rather slowly, if it will work at all, on pests in Southern Nevada.

Bt works on those insect larvae that mature or pupate into either moths or butterflies. So if the larva turns into a beetle, for instance, it will not work. Without knowing what insect larva you have it is hard to know what will work unless you use a conventional pesticide approved for use on vegetables and has insect grubs or larvae on the label.

This time of year Bt is a good product to use in home gardens because of the presence of cutworms. I am sending you a picture of what the cutworm larva looks like and its adult form (this is also posted on my blog), a moth. Bt can be sprayed on the soil and left undisturbed (no hoeing or irrigating) for a few days.

This is the time of year that this moth is flying and laying eggs. Their larvae hatch from the eggs and are out looking for food right now. Usual cutworm damage is at the soil surface, not on the leaves.

Other products to try to protect your plants are those that leave a poisonous residue for insects on the leaves. You also can use insect netting to cover the rows in a low tunnel.

Bob Morris is a horticulture expert living in Las Vegas and professor emeritus for the University of Nevada. Visit his blog at


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