What's Hot Archive 2021
What's Hot in January
How can I protect my citrus trees from frost damage?
Citrus trees benefit from being planted in a sheltered area. Healthy, well-irrigated trees are better able to endure freezing temperatures. Keep the ground around citrus trees bare because bare, moist soil is better able to absorb and reradiate heat than soil covered by mulch or other ground covers. Young trees (one to three years old) can also be covered entirely, using a light material to trap heat being radiated by the ground. A frame or stakes should be used to minimize contact between the cover and leaves because ice may form where the cover touches any leaves. Sheets, burlap, or tarps are a better choice of cover material than plastic because plastic transfers more heat and if leaves come in contact with it they are more likely to freeze. The cover should extend as close to the ground as possible and be removed the next morning after the temperature rises.
For more information see:
Frost Protection for Citrus and Other Subtropicals
Avoiding Cold Damage to Citrus (pdf)
What's Hot in February
Are my limes still usable after they turn yellow?
Absolutely! In fact, all lime varieties resemble lemons when allowed to ripen fully. In the ripening process, from their first, yellowish blush to full lemon-like maturity, limes become juicier and less acidic - which explains why the green fruits found in grocery stores are often hard and disappointingly dry. Why, then, do stores sell limes before their time?
When ripe, this popular citrus is too soft to be processed and shipped without damage, so farmers pick the fruits while they're still green. Once removed from the tree, the ripening process stops. As a result, we've become so accustomed to buying green limes that the occasional yellowish one in the produce aisle seems suspect.
Some people prefer the puckery tartness of green limes, so you might try some experimentation to determine what stage of ripeness is just right for you.
Learn about growing limes.
What's Hot in March
I’ve read that vegetable seedlings grown indoors need “hardening off” before they’re transplanted, but what does that mean, and how do you do it?
The process of hardening off is a bit like a two-week Charles Atlas course for delicate seedlings, without the push-ups. Gradually exposing your tender youngsters to the harsh realities of the great outdoors will transform those 98-pound weaklings into beefy specimens, which are then better able to grow into strong, productive plants.
The term itself is quite literal: exposure to less hospitable conditions signals to the plant the need to toughen up. This initiates a process that creates an accumulation of carbohydrates in cell walls, creating thicker, woodier plant material. Properly hardened seedlings are unfazed by sun, wind, light frosts, or even getting a bit of sand kicked in their faces.
Read Tough Love: Hardening Off for more information.
What's Hot in April
Should I start watering my mature trees yet?
By April, any chances we have at upping our rainfall for the Water Year are pretty much toast. Due to the abysmal numbers for Water Year 2020–2021, (about 10 or so inches, compared to an average of roughly 18–24 inches) mature trees in particular need some extra love. An easy way to do this is by looping a 25-foot soaker hose around the base of the tree, within or at the drip line, turning the hose on very, very low, and letting it run slowly through the night. This month, run your soaker hose once or twice, and increase to once a week by July and until the heat of summer and early fall is done. The water use is truly minimal, and your tree will thank you by making lovely shade for you throughout the summer.
Photographer: Laura Kling
What's Hot in May
What do I do about aphids?
Warm weather, and the flush of new tender growth on ornamental and edible plants invariably attracts the aphids. They come in an astounding variety of colors and preferred host plants, although some are generalists and enjoy most any type of plant. These soft-bodied sap-sucking beasts can damage young plants. Some sources say they will not destroy a plant, but experience begs to differ. Your best defense against aphid infestations is to inspect your plants regularly (even daily) for their presence. Look closely, as their body color can mimic that of their host plant, and be sure to check the underside of leaves. Spray them with water (either from a bottle or from your hose) strong enough to knock them off the plant without damaging new growth. Stronger measures include spraying with neem oil or other horticultural oils. Natural predators, including lacewing, lady beetles, and even birds, normally follow an aphid infestation by a week or two. Please see UC ANR Pest Notes on aphids for more details.
Photo: Potato aphids are larger and more elongated than green peach aphids. The tubercles at the base of the antennae do not converge as they do in green peach aphids. Photographer: Jack Kelly Clark, UCANR
What's Hot in June
Help! I think I have whiteflies on my vegetables!
Tap your plant or brush by it and a cloud of tiny creatures rises and scatters. These are most likely whiteflies, very small insects that are close relatives of last month’s nemesis the aphid. Whiteflies come in hundreds of species. They are found on a wide variety of plants, from ornamental flowers to warm-weather vegetables. Like aphids, whiteflies have piercing, sucking mouthparts and produce a sticky substance known as honeydew. Heavy whitefly infestations can damage plants: leaves will wilt, turn pale or yellow, growth will be stunted, and eventually leaves may shrivel and drop off the plant. To control whitefly populations, inspect plants regularly, especially new growth. Be sure to check the underside of leaves where they congregate and lay their even smaller eggs. Blast or spray with water regularly, or with insecticidal soap up to several times a week. Natural predators include ladybugs, spiders, green lacewing larvae, dragonflies, and hummingbirds. Attract beneficials by including plants that flower throughout the spring and summer. Please avoid chemical insecticides as they are not often effective against whiteflies and will kill beneficial insects—their natural predators. If you are buying your vegetable starts, make sure you inspect them for infestations before purchasing them and bringing them home. Read the UC IPM Pestnotes on whiteflies.
Photographer: Jack Kelly Clark, UC ANR
What's Hot in July
What is the best time of day to water?
No matter what you are irrigating, or how, the very best time to water your plants is in the wee hours of the morning. Broadcast or drip, lawns, shrubs, vegetables, or flowers, your plants will do best when watered early in the day before it is light out. It seems counterintuitive that you can conserve water while watering, but if you irrigate before the sun is up, you reduce trans-evaporation, and ensure that almost every drop applied makes it to the roots of your plants, where it is most needed. In addition, the moisture will help keep the soil a tad cooler when temperatures rise during the day. Lastly, irrigating in the evening hours before dark can encourage fungal growth on leaves. Because an early morning irrigation regime is hard to monitor for leaks and breaks (you may be sleeping while the irrigation runs and small leaks are hard to detect in the dark), be sure to check your system (lines, emitters, etc.) seasonally.
Photographer: Laura Kling
What's Hot in August
Why does a limb suddenly break off and drop from trees?
Seemingly out of nowhere, a large limb will break off a healthy tree, and crash to the ground. This phenomenon, known as Sudden Limb Drop, Summer Limb Drop, and Sudden Branch Drop Syndrome occurs primarily on hot summer days, and most commonly in oak, cottonwood, sycamore, and walnut trees (among others). It affects trees in watered landscapes and native trees that aren’t irrigated. Although a number of causes have been posited over the years (please see our Real Dirt article “Summer Branch Drop in Oaks” from 2015), experts at UC Davis now believe that during high temperatures, trees pull water from the ground faster than they can release that moisture into the air. As a result, limbs become too heavy, crack (usually about three to twelve feet from the trunk), and fall. Limbs that fit the profile for this syndrome are large, mature limbs, growing horizontal to the ground and extending beyond the main canopy of the tree. Usually, a few seconds before the branch falls, you will hear a loud crack—your warning to get out from under that tree!
Photographer: Olivia Danielle Ruiz
What's Hot in September
Is it safe to eat food from my garden if it’s been exposed to smoke and ash?
The information below is quoted (with permission) from the Butte County Local Food Network’s August newsletter. You are encouraged to follow the links below to learn more about the effects of fire, smoke and ash on our plants.
“We are asked sometimes about the impact these fires might have on garden produce. There are some helpful articles online that we wanted to point you to. What should I do about the wildfire ash covering my yard and garden? is from Oregon State University’s Extension Office. It links to another put out by the EPA that many would find useful. Food Safety after Urban Wildfire from UCCE Sonoma that is pretty in depth. It also has a link to a video/webinar on how to safely grow food or keep poultry after a burn.
[For those of you wanting to learn more about how the native peoples in this valley dealt with fire, our] … best local resource is Ali Meders-Knight at Chico Traditional Ecological Stewardship Program, and the "Camp Fire Restoration Project.”
Photographer: Sam Angima
What's Hot in October
What are these red areas in my manzanita and how do I get rid of it?
The information below is summarized from the UC IPM website; see the entire report.
Those “growths” on the manzanita are galls, caused by the manzanita leafgall aphid (Tamalia coweni). Per its common name, this gray or greenish aphid feeds only on manzanita, and can produce several generations per year. These aphids, and the galls (a green or reddish pod-shaped swelling on leaves), are generally harmless to the plant, but heavily infestation will slow a plant’s growth.
Since manzanita leafgall aphids are prevalent on new growth, avoid frequently fertilizing, irrigating, and shearing plants (in general, manzanitas do prefer to be left alone). Do not irrigate too frequently or with excess amounts (again, few manzanitas require irrigation). If aphid infestation and gall growth were heavy the previous season, you can apply horticultural oil to lower trunk bark when buds begin to swell but before they burst into new leaves. For more information, also consult the Pest Notes: Aphids.
Photographer: Jeanette Alosi
What's Hot in November
How do I tell when pumpkins and other winter squash are ripe and ready to pick? How should I store them?
One way to tell if your beautiful and nutritious pumpkin, butternut, and other winter squash are ready to harvest is to follow the “days to maturity” count from the seed packet, especially if you are one of those organized persons who keeps a garden diary, or you have a phenomenal memory. In the likely event that neither of those descriptions apply to you, UC Agriculture and Natural Resources notes that “winter squash are ready to harvest when the rind hardens and the skin takes on a dull cast. Check the stem with a fingernail; if the skin can't be dented, the squash is ready.” Helpful hints for storage include: "when harvesting winter squash, use a knife and leave a two-inch stem on the squash to help it last longer. Store winter squash and pumpkins in a dry, fairly cool location (ideally 55 to 59ºF at 50 to 70% relative humidity). Under these conditions, if you harvest mature, not over-ripe fruit, you can expect a storage life of up to 60 days.”
Bonus information about curing squashes for a longer storage life, and more details about the differences in winter squash.
Photographer: California Condor
What's Hot in December
Should I water my plants this winter?
It’s not news that the last few winters have brought very little rain and snowpack to our region. Consequently, natives and low water plants in our landscapes that normally would last through the summer without much supplemental water suffered badly. Those of us here at enews lost some hardy and well-established plants due to dismal winter rainfall totals, coupled with especially hot and dry summers.
The short answer is, yes, especially if we experience another dry winter. Our last couple of winters have delivered about one-half to one-third of the average rainfall to the valley and the foothills of our region.
- With dry winter weather, water once a month, possibly twice.
- Water only when the air temperature is above freezing, early in the day.
- Water turf grass, especially newly planted or seeded lawns.
- Evergreen trees need more water than deciduous ones.
- Any plant with shallow root systems is more susceptible to winter damage.
- Remember to water newly planted bulbs as well so they will sprout in the spring.
Surprisingly, the purpose of winter watering is not to provide water for the plant to draw up its stem but to prevent the roots from desiccating in the cold dry ground.
Photographer: Bas Leenders