Many of us deal with less than ideal soil here in Benicia. Whether too much clay, too much sand or a history of contamination, dealing with poor soil can hinder potential harvests. As an organic gardening practitioner, I am in the business of ongoing soil-building. By amending the soil of our orchards with organic matter and by green mulching, we can see marked improvement to soil tilth over seasons of cultivation.
While building soil is a constant practice for long-lasting organic farming success, this season’s growth and plant nutrient uptake can be enhanced, not just by the plant’s roots as might be imagined, but rather by the plant’s leaves directly. If getting an added boost in your orchard or berry farm’s production by applying foliar spray piques your interest, read on.
In his book “Plant Life in the World’s Mediterranean Climates,” Peter Dallman describes the way that plants have adapted to surviving drought. “Leaves lose water mainly through small surface pores that are lined by specialized guard cells, regulating the size of the opening to a chamber underneath.” These stomata “function as hydraulic valves, adjusting pore size according to; light intensity, temperature and humidity.”
In the case of arid-adapted species, such as many of the 6,000-plus plants native to California, these plants have become masters of closing these stomata to slow metabolism and to retain moisture. This allows the plants to temporarily open the stomata in storms to maximize growth and then to hunker down and conserve for the long six to 10-month drought we often experience here in the arid Bay Area.
As a measure to conserve agricultural water, many growers have switched to drip irrigation. While this greatly lessens water wasted by overhead sprayers, this practice delivers the water to the root zone or rhizosphere of the plants, leaving the leaves dry above. Since stomata are responsible for regulating metabolism, those of us saving water on drip irrigation can boost plant health by spraying foliar nutrients. For those of you unfamiliar with this term, foliar feeding means to apply nutrients in a liquid spray that is applied directly to the leaves of plants, allowing nutrients to be absorbed immediately through the vasculature of the plant. Despite limited water usage and less than ideal soil tilth, we can support increased growth capacity with weekly foliar feeding.

Plants that benefit from foliar spray:
-Berries
-Leafy greens
-Culinary herbs
-Citrus
-Apples
-Pears
-Tomatoes
-Peppers

Plants who do not like foliar spray:
-Curcurbits *(Squashes, Zucchini, Melons) Grapes

Kelp Meal
Kelp also boosts the vitality of orchards. All spring and into summer, I spray a dilute kelp spray on orchard leaves once per month just before sundown in the months of April, May and June. This way, during the vegetative period before the Summer Solstice, the health of the developing orchard leaves is maximized and thriving such that they cannot support disease as readily. With berries, being fast growers and apt to mildew, I spray 1x/week and switch just after the Summer solstice from Vegetative kelp to Flowering kelp *(See below.)

—-For Vegetative Plants:*(early season growth and leafy greens)

I recommend Age Old Kelp .30-.25-.15

Joshua’s recommended dosage:

—Rooting cuttings: an application rate of 1 teaspoon/gallon. (Note: 3x/week until roots show strong growth)

—Vegetable, Berry and Orchard Spray: 1 oz/gallon. (Note:spray 1x/week up until fruit set.)

Liquid Fertilizer: http://www.planetnatural.com/product/age-old-kelp/

—-For Flowering Plants *(Pepper, Berries, Tomatoes)
Down to Earth Brand’s Kelp + Potash 0-0-8

Joshua’s recommended dosage: application rate of: 1 oz/gallon.

Liquid Fertilizer: http://downtoearthfertilizer.com/products/liquid-fertilizers/liquid-kelp-potash-0-0-8/

Worm Tea
Worm castings tea works wonders for plant growth potential whether in a root drench or in foliar feeding production crops. Did you know that being pH balanced, in theory one could plant in pure castings and they would not burn? Nevertheless they are far too valuable and coveted. In addition to putting 5 percent castings into my soil blends, I also recommend a low tech and simple worm tea. Again, spraying once per month just before sunset spring, summer and fall allows for the microbes to neutralize the leaves and consume any bacterial or fungal imbalance while increasing its immune system. In this way the plant is given preventative medicine while in the same action providing nutrients straight into the vasculature.
At $20 per bag, this black gold is a valuable commodity. Consider setting up your own Vermi-bins to harvest these black pearls of pH balanced nutrition.
Dosage: 2 cups of worm castings per 5 gallons of water in a cheesecloth and soaked overnight.
(Note: Foliar should be applied at dusk when sun ray’s are no longer direct.)

Want to learn about setting up worms?

Read This book:
“Worms Eat My Garbage” by Mary Applehof

Peppermint Essential Oil

With the shortening of days in autumn comes a heightened potential for infection from bacteria and mold, as well as infestation of insects that prey on the weakened plants. Especially with fruiting bodies, from tomatoes to peaches to grapes, when the sugar content in a fruit increases, so too does the risk of infection in that high sugar environment. Not unlike candida outbreaks in diabetics, once the pH of an organism is off, it becomes easier to infest. We can feel the dew point increase each evening as the solar period lessens and the soils ambient temperature diminishes. At this point each fall the goal is to get the fruit to mature without damage from bacteria, fungus or insect. I have had great luck with a few simple products. One of my favorites is peppermint essential oil. I use 10 drops per gallon of water diluted into a backpack sprayer up to once per week just before sundown allows aphids and powdery mildew to be controlled year-round on my leafy greens. The brassicas in particular respond especially well to this weekly spray regimen. Many horticulturalists recommend spraying Neem oil, but in my opinion it gives food crops a strange flavor even after thoroughly rinsing. The peppermint oil however lingers on the leaf creating an environment that mold nor bugs seem to like.

Joshua recommends:
DoTerra Peppermint Oil
Dosage: 10 drops/gallon

Foliar spray can help keep your orchard or berry patch for longer into the season, so that pestilence has a harder time getting established. This added time can be the difference maker to get fruit set mid-season, and then utilize some of these organic sprays to fend off fall pestilence. So get yourself a spray bottle and one of the ingredients listed above. One evening this week, just before the sun’s rays crest the Western horizon, spray your veggies and see marked improvement.

Joshua Burman Thayer is an ecological landscape designer specializing in drought tolerant food production. He can be reached at (510) 332-2809. For more information, visit www.nativesungardens.com