Questions Submitted for our June 13th Webinar

From fog: Choose resistant varieties; get as much sun as possible and prune.  Avoid sprinkler systems and watering in the evening.

From wind: Gardens on north and west side of properties in our County are the windiest. You can block wind with shrubs, open fences to let a little bit of air temper the wind, lightly covered open fence with vines, lattice-work, or a 50% shade cloth.

Beets: When the beet shoulders protrude above the soil line.

Garlic: Tops will fall over and begin to get brown or yellow.  Dig out, not pull out. 

Radish: Record the planted date and expected maturity date from the package. About 25 days from planting in the summer and 50 days in the winter.

Not necessarily, if used cautiously. Read the label carefully; get the MSDS. Use on non-windy days in morning; wear gloves, eye protection. If possible use something other than pesticide.

Spider mites like dry arid weather. Suggestions that I found were: insecticidal soaps and oils such as neem oil, rosemary oil and water, pepper spray, diatomaceous earth. Also, I’ve used lady bugs with some success, and six spotted thrips.

I live in central San Francisco. Meyer lemon trees grow quite well, particularly if next to a wall that will reflect heat. I’ve also seen old fashion lemons used as a hedge in Cow Hollow on the north side of the street. As for cherry trees, the Kwansan, Yoshino and Okame are the most popular in the Bay Area.

Lemon: The Eureka and Lisbon lemons grow well but are very thorny so unpleasant to prune! The Improved Meyer is a good all-around choice.

Ornamental cherry: Pink star (“Ben-Hoshi”) and for weeping style: Akebono and weeping Higan cherries. For actual fruiting cherries I’ve heard that the fairly-recently-introduced Minnie Royal and Royal Lee are doing well in our area – and can pollinate each other.

Tomatoes and squash have the same nutrient requirements: Low nitrogen, High phosphorus and medium potassium. Basil calls for a more balanced diet with High potassium, very low nitrogen and even lower phosphorus. And the beets need moderate potassium and nitrogen and high phosphorus.

It looks like what loopers a form of caterpillar might do. There are several things which you could do: plant flowers such as alyssym, daisy; or dill to attract beneficial insects or use BT (bacillus Thruingiensis) which is a naturally occurring bacterial disease which attacks caterpillars and is considered organic. It’s used on crops and ornamental plants and sometimes for organic agriculture.

It could possibly be banded cucumber beetles or striped cucumber beetles.  If the watermelons are planted near cucumbers, squash or cantaloupe. It could also be by cutworms which are present in the soil. The best things to use are insecticidal soaps or pyrethrins. They are toxic to the insect nervous systems and are biodegradable.

Your first line of defense is good cultivation practices:

• Be liberal with annual or twice a year composting. If you feed the soil you feed the tree. A healthy tree can fight off many pests.
• Pick up any lemons that drop from the ground.
• Manage the ants: use a sticky band, such as Tangle Foot to keep ants from defending and farming aphids and other pests that produce sweet honey dew.
• Keep some flowering plants near your lemon tree and throughout the garden to attract beneficial insects such as parasitic wasps, lacewings, lady beetles, hover flies, etc.
• Oil sprays such as Neem can suffocate and also repel many common pests – but may harm bees, so don’t apply during the day.

Roses:

Best to use good cultivation practices. Make sure the rose has lots of sun, good air circulation, and is watered at the soil and not from overhead. Rust needs moisture to take hold on the leaves.

Remove diseased leaves from the plant and ground.

Compost and mulch. Healthy plants can better repel pests and disease.

If necessary, use fungicides such as Serenade or sulfur; but if rust persists, it might be better to replace the roses with resistant varieties – especially if you are coastal.

Apple Trees:

Without good heat and sun, apple trees are prone to powdery mildew.

If you don’t have the heat and sun, fungicide sprays will be necessary – but it might be best to replace with a resistant variety such as Red Delicious and Stayman winesap.  Golden Delicious, Braeburn, McIntosh and Granny Smith are also fairly resistant.

Neem oil or Serenade would be effective if you can coat both sides of the leaves.

Prune out branches if needed to open up the tree to air and light. 

See if you can find where they live and what they eat. Keep their living area moist as they need dry; remove food sources if possible. If they are going up trees and shrubs, put a band of sticky substance such as TangleFoot around the trunks to keep them from feeding on aphid or white fly excretions (honey dew).

Diatomaceous Earth can be sprinkled around their nest if it is not an area frequented by bees that might be crawling around. You can also spray trails and nests with Orange Guard – an orange peel extract. Look at garbage and other likely areas for ant congregation and spray there, too.

A baited trap can be effective if these fail: use boron- or spinosad-based baits as the least toxic products.

Really depends upon the type of ant.

Cultivation, barriers and insecticide baits or sprays around base of plants.  Argentine aunts can be controlled with farnesol a behavior modifying chemical a pheromone.

I use spray soap or windex to get rid of the trails. Sometimes I take apart Grants Ants and that solves the problems.

Also, baits with boric acid, fipronil, avermectin or hydramethylnon are good. A liquid borate, about half to 1 percent borate in sugar water solution is good for Argentine ants. PestNotes on the UC website is a good resource. Whatever you use should be slow acting so that they don’t die before they get back to their nest.

For container plants, sticky material, slippery Teflon sprays or wraps or moats of water or oil will exclude ants from container plants or growing benches. Spraying the soil surface or drenching soil around the nest with certain insecticides also reduces ant populations.

Food grade Diatomaceous Earth is safe for pets. It kills crawling insects so isn’t effective on flying critters. It can be bad for bees as they can do some crawling around.

You might have fungus gnats – and their larvae feed on decaying vegetation such as grass in a too-wet lawn. Diatomaceous Earth might control them. You can also use the organic fungal spray Bti ( Bt var. israelensis (Bti), also called H-14 strain. Predatory nematodes might be the best choice as they keep other pests in check, too, without harming bees.

See what these little bugs are living on, if possible. Dog poo? Dropped fruit? If such things are removed, your problem might go away.

Also, they might be a seasonal problem so you might not have them for long.

Neem oil is effective against all stages of whiteflies. Apply to the underside of the leaves every 4-6 days. Horticultural soaps are also effective but must be used in a high concentration and might damage some plants – so test first.

Use reflective mulch, which you can purchase, or cut up reflective plastic or shiny construction paper

Control dust and ants    

Yellow sticky traps can reduce their numbers.

Many beneficial insects prey on white flies, so have  a variety of flowering plants nearby to encourage lady beetles, lacewings and parasitic wasps.

Don’t use insecticides that will kill the beneficials. Also, whiteflies rapidly develop resistance to chemical controls, so they quickly become ineffective.

Yellow leaves can mean many things:

The lower, older leaves typically turn yellow and then wither;

Or the soil has been too wet and caused root disease (the center leaf yellow splotch might indicate that). Dig alongside the plant to see if the roots are white and healthy or brown and withered.

Our local soils are generally low in nitrogen, and yellowing on the older leaf might indicate a need for additional nitrogen. Organic fertilizers such as blood meal and fish emulsion will remedy nitrogen deficiency. Follow directions and know that too much nitrogen will mean a lot of green growth at the expense of the cucumbers!

To help your soil and your plants — add some compost now and lots more after harvest to build up nutrients in your soil for next year’s crops

Neem oil is one of the safest pesticides in the gardener’s arsenal. It poses no known risk to water quality or aquatic wildlife; its potential harm to beneficial insects is low; risk to humans and other mammals is very low.

Cons: It does harm honey bees so only apply during late evening, night, or early morning. This is also helpful because the oil should not be applied in the heat of a hot day or it can damage foliage. You need to apply it thoroughly – all plant surfaces, so it can be difficult on trees or bushy shrubs.

It is effective against aphids, but so is a jet of water. If you hose them off they can rarely climb back up a plant.

It’s a good product for powdery mildew – less effective on rusts.

Kurapia for a grass replacement – it will attract bees and you must be rid of weeds and weed seeds before planting it. Other water-wise alternatives are the more grass-like Berkeley sedge  or red fescue. You might mix the sedge and fescue together and even with flowering and low-growing plants such as yarrow (Moonshine), arctotis ‘ultra Violet’, poppies, oreganos and marjorams, etc.. All these can be mowed if desired.

Not knowing the size of your property and so what would be too big or too small, I’ll go in order of smallest to largest:

• Santa Barbara daisy – banks of small daisies
• Lavender angustifolia (English lavender)
• Various small azaleas if some shade or you are coastal 
• Compact Coleonema – Pink breath of heaven
• Rhaphiolepsis Indian Hawthorne Monto 
• ‘Indian Princess’
• Skylark ceanothus (or other suitable small ceanothus)

Pineapple guava, camellia, Japanese maple — or a nice ornamental trellis with a light vine such as clock vine, black-eyed Susan, or jasmine for fragrance. These all let in light. The Japanese maple is deciduous so will let in more light in winter than the others.

ID your pest—gopher or mole?

• Best Predators:  Feral cats – Heading Home Animal Rescue
• Gopher-resistant plants—LOVE tap roots—poppies and most bulbs, except for daffodils and amaryllis
• Resistant:  most succulents, many CA natives, gopher spurge
• *Never use chicken wire
• Cage or protect veggies or expensive gopher-loving plants, such as:
  • Phormiums
  • Roses
  • Lavateras – rose mallows
  • Root veggies
  • Expensive trees or orchard trees with 3 ft. X 3ft. ½” aviary wire cage
• No commercial tree cage large enough— root girdling.
• Underground horizontal wire barriers best for turf or ground covers.
• Underground vertical fence at least 2 to 3 feet deep and 6 to 12 “ above ground.
• Trapping is the best alternative—Cinch or Gophinator, but need to practice
  • Trapping will make a dent in population
• Irrigated yards will attract more gophers. 
• Barren strips help

Slugs (and snails): 

• Check or Eliminate hiding places – slightly elevated boards, rocks, phormiums (or other reedy plants), tree trunks, dense groundcovers (ivy), water meter boxes, pots
• Switch from overhead irrigation to drip and irrigate in mornings.
• Prefer seedlings and succulent foliage
• Hand-picking at night with flashlight or headlamp
• Decrease depth of mulch.
• Beer-baited traps buried at ground level
• Copper foil or tape, but don’t work after tarnished.
• Chickens, ducks, and geese eat them.
• Baits – iron phosphate OMRI approved.

“Feed your soil, not your plants” – Master Gardener mantra

• Microbes (bacteria, protozoa, and fungi) are critical to all life on earth
  • Far more beneficial microbes than pathogenic
  • More microbes in 1 tsp. of healthy soil than there are people on earth!
  • Soil food web.
  • What do most microbes need to survive
    • Food, water, and oxygen
    • Food: Organic matter—roots are preferred food, then compost, leaves, plant debris, wood mulches, etc.
• Can expect better health and growth almost immediately, especially if compost is tilled in. Restructuring does take time, though, so “no-till” gardening is becoming popular.
• Basic Soil Amendments (for our soils)
• For ideal, loamy soil, add the following to the soil surface:
  • ½” of good-quality compost or herbivore manure*
  • A sprinkling of oyster shell meal or ground egg shells (for Ca)
  • A sprinkling of kelp meal (for micronutrients

• For sandy or clay soil, gently fork in to the top 4” to 6” of soil:
  • 1” to 2” of good-quality compost or herbivore manure*
  • a sprinkling of oyster meal or egg shells and kelp meal
• For never-before-worked soil or extremely hard, clay soil:
  • May need double-digging or deep tilling
  • Greater amounts of amendments would be incorporated as dug

*Note: manures must be well-aged and not advised for root crops

Kale, Lettuce and Carrots are cool season crops, so best planted in early spring or late fall. Heat will promote flowering and bolting.

Year-Round Gardening Guide on Master Gardener site (under Gardening Resources – Vegetables, Herbs, and fruit) for Foggy, Sunny, & Hot areas. Taken from Golden Gate Gardening by Pam Peirce

Sandy loam soil is ideal -rocks and clay inhibit growth.

12 to 18” depth

Avoid high nitrogen fertilizers, which promote green growth and not root growth.

Avoid manures and use compost instead.

Super Greensand can be added for potassium and other micronutrients.

Need 6 to 8 hours of sun.

Roof and Norway rats:

• Both forage at night
• Gnaw through almost anything
• Jump 3 ft vertically and 4 ft. horizontally
• Burrow down 4 ft.
• Can squeeze through ½” of space

Roof rats:

• Black and smaller than Norway rats
• Nests off the ground—shrubs, trees, attics, ivy
• Great climbers—any rough vertical surface and conduit up to 3” wide

Norway rats:

• Brown and larger
• Nest in burrows, basements, wood piles
• Better swimmers

ID:

• Look for droppings, gnawed branches, nests, attic noises
• Use flashlight to scan fences, utility lines

Habitat modification:

• Remove dense vegetation—ivy, old agapanthos,
• Prune back tree branches to at least 3 to 4 ft. from roof or other trees
• Remove pet food and bird seed
• Remove dropped fruit
• Cover compost bins

Rodent proofing:

• Ventilation screens
• Secure crawl space doors
• Seal gaps around pipes with sheet metal or steel wool
• Spark arresters
• Cover roof vent pipes with screens
• Weatherproof exterior doors at bottom
• Netting messy and often ineffective
• Enclosed garden beds or trees with wired panels

Trapping:

• Abco electronic rodent zapper
• Snap traps- wooden and plastic
• Leave traps unset for couple of days
• Place perpendicular to walls or back to back along fences
• Nail wooden traps to beams
• Goodnature A24 automatic trap – CO2 cartridges with plunger.

Blackberries are a very invasive plant and even if you cut them back they’ll just grow back more vigorously. The only way to get rid of them is to dig out the roots, which is obviously not ideal for your native plants that the blackberries have grown up around. If you don’t want to dig, you can cut them back, but this is a temporary solution. Roundup is not something you want to use — it has been found to be very toxic, and has a long residence time in the soil.