Q. I have a young avocado tree. I’ve had it for about 2 years now. It’s planted in a mega pot and growing nicely. My concern is that the leaves seem to get sunburned. It still has lots of new growth, but the older mature leaves get dry and burned-looking.
A. Plants that grow in containers for any extended period (a year or two) can suffer from salt burn. This will cause older leaves to turn brown along the edges before completely drying up and falling off.
In areas with hard water, repeated irrigation deposits minerals into the soil and onto the sides of the container. Sometimes it’s visible as a white crust, especially on the outside of terracotta pots.
These minerals can be flushed out periodically by flooding the pot and letting the water drain freely out of the bottom.
Q. I’m curious about the vegetable washing sprays and solutions sold in the produce department. Are they any good? Is there a cheaper alternative that I can mix up at home?
A. In most cases, safe food handling practices combined with thorough rinsing in clean water is sufficient. The greatest danger of contamination comes from contact with raw meat or fish, so take care to bag meat and fish separately from produce and store them separately as well.
Always wash produce under running water and, when possible, use a brush to scrub the surface of firm vegetables and fruit before cutting. This is especially important when preparing cantaloupe since the netted outer rind tends to get dirtier due to its texture. The vegetable brush can be sanitized by running through the dishwasher or rinsing in a solution of one teaspoon of chlorine bleach diluted in one quart water.
Don’t use dishwashing liquid or antibacterial soap on produce since they can leave residue that could be harmful.
Many brands of vegetable washes/sprays have appeared in the last three years. Some are labeled “organic,” but that doesn’t mean they are effective at removing more dirt and pesticide residue than simple rinsing. Most contain some combination of essential oils and surfactants. There haven’t been many studies done on their effectiveness, so I can’t tell you for sure if they are worth buying or not.
A related concern is how to remove aphids and other clingy insects from craggy vegetables such as broccoli and cauliflower. No matter how vigorously I rinse and brush, I can never get all (or even most) of the aphids out. Blanching for a minute in boiling water, followed by a dip in ice water and another good rinse will usually do the trick. Alternatively, a brief soak in a bowl of salty water can dislodge those stubborn aphids.
Los Angeles County
mglosangeleshelpline@ucdavis.edu; 626-586-1988; http://celosangeles.ucanr.edu/UC_Master_Gardener_Program/
Orange County
ucceocmghotline@ucanr.edu; 949-809-9760; http://mgorange.ucanr.edu/
Riverside County
anrmgriverside@ucanr.edu; 951-683-6491 ext. 231; https://ucanr.edu/sites/RiversideMG/
San Bernardino County
mgsanbern@ucanr.edu; 909-387-2182; http://mgsb.ucanr.edu/