It might well happen that, some time in the not too distant future, Los Angeles parkways, those woebegone pieces of earth between sidewalk and street, will be transformed into vegetable gardens.

For years, I have laughed at parkway lawns. They are nothing but a headache and a waste of water. Aside from the constant irrigation required to keep parkway lawns green, the sprinklers embedded in the parkways do an excellent job of watering cars parked along the curb. This results in much consternation if not violent outbursts on the part of those hapless souls who, unknowlingly, park along the curb only to discover that their recently waxed vehicles are covered with water spots.

Enter Ron Finley, a denizen of South Central Los Angeles, who started growing vegetables in the parkway parallel to his home. The city came along and told him that he would have to pay $400 for a permit that would allow him to keep his curbside cornucopia. Finley resisted, his city councilman was contacted, and his garden was left alone.

One night Finley came upon a mother and daughter taking food from his garden. Unperturbed, he encouraged them to harvest what they needed. When asked by a reporter whether he was concerned about people stealing his food, he replied, That’s why it’s on the street. That’s the whole idea. I want them to take it.”

Curbside gardens are examples of those proverbial random acts of kindness that could change the world. I don’t think anyone would argue that the world could use a change or two and so, as gardeners, we might want to consider planting more edible curbside gardens.

Question: I understand that coffee grounds provide acid to the soil and that citrus and hibiscus plants need acid, so I have been putting my coffee grounds around a miniature lemon tree and a large hibiscus bush. Is this a good idea?

– Linda Stephens, Camarillo

Answer: Coffee grounds are an outstanding product for the garden, both as soil amendment and as fertilizer. Southern California soil, like soil throughout the Southwest, is usually alkaline and most plants — including vegetables — prefer a slightly acidic pH of about 6.5 so it makes sense to add coffee grounds to our soil. If you have a heavy, poorly drained soil, you can amend it up to 35 percent by volume with coffee grounds which, like other amendments, aerate soil and enhance drainage capacity.

Coffee grounds are also a fertilizer, containing 2.28 percent nitrogen, .06 percent phosphorus, and .6 percent potassium. In acidifying the soil, coffee grounds break down soil minerals that contain phosphorus, potassium, magnesium, and copper, making these essential nutrients available to your plants. You want to exercise caution in application since big piles of coffee grounds on the soil surface will be contaminated by fungus. As is the case with any kind of kitchen waste used as a topical fertilizer, it is best to allow your coffee grounds to age somewhat, whether in a compost pile or by themselves, before application. And, ideally, coffee grounds should be sprinkled or lightly applied to the soil surface.

Question: We heard that carrotwood trees (Cupaniopsis anacardioides) come in female and male types. We were wondering about this because of the abundance of seeds. If carrotwood trees are indeed female and male, how can we the consumer determine the gender of the plants at the nursery?

– Michael & Jerri Barba, Pico Rivera

Answer: The flowers of most plants and trees are perfect, meaning that both male and female flower parts are found together in every flower. Imperfect flowers have exclusively male or female parts, and are found on two categories of plants, known as monoecious and dioecious species. Monoecious species, such as oak, birch, carrotwood (prune it and you will see that its wood really is carrot-colored inside), alder, sycamore, sequoia, cypress, walnut, cedar, corn, and many grasses, have separate male and female flowers on the same plant. Dioecious species, such as date palm, pistachio, carob, kiwi, holly, willow, poplar, podocarpus, ginkgo, and juniper have separate male and female plants. There is no way you can tell by looking at a dioecious plant, prior to flowering, whether it will be a male or a female. You just have to be patient and wait until it flowers to find out.

Question: I just planted several 15-gallon Agave Vilmoriana, ‘Stained Glass’ variety, on a rocky hillside slope above my home. They were newly planted alongside Myoporum to prevent hillside erosion just three weeks ago. All of the agaves are southern-facing and many are experiencing leaf wilting and some yellowing. The do receive a great deal of sunlight daily (more than eight hours a day) and it has been quite hot recently. The crowns do get hit with water twice daily (once at 7 a.m. and then again at 1 p.m.) from the sprinklers. Is the leaf wilt a result of too much sun exposure, over or under watering, or water hitting the crowns? I think if they keep going in this direction, they will not make it. What should I do?

– Andrew Becker, Pacific Palisades

Answer: Many leafy succulents and all soft-leafed agaves, such as Agave vilmoriniana, are sensitive to pounding sun. Furthermore, the fact that you just planted them — and that acclimation is needed before plants feel at home and can withstand the sort of stress created by our recent heat wave — would explain the symptoms you describe. Once a day watering, even where new plants are concerned, should be sufficient in Pacific Palisades, although this recent heat wave may require additional watering.

You want to avoid watering the crown (where plant meets roots) of succulents, if possible. You might also want to apply SuperThrive to your Agaves. This product, available in most plant nurseries, contains root hormone and helps plants establish themselves in less than perfect growing conditions. I don’t know if it is practical to mulch the area but mulching is wonderful since it significantly reduces irrigation frequency and the less often you have to water, the better your plants grow.