Guarding the Grapes

September 23, 2018

neem

The predictable announcement was, “Yum!” from anyone who tasted our Interlaken table grapes. One taster cocked her head and let her eyes drift upward, savoring the sweet with a little tart sensation.

We were thankful to have a few grapes this year! Last year was a bust due to powdery mildew. In 2017, the grape clusters shriveled and dropped. We knew we needed a plan for the 2018 season.

Our first step was to sign up for another class from the grape guru Michelle Moyer (WSU – Prosser).

Michelle explained: Powdery mildew (Erysiphe necator) comes in many forms. A vine is most susceptible when temperatures are 68F to 86F and humidity is moderate (40-75%), conditions that are quite common in Western Washington during the growing season.

Sat, Oct 6, 2-5, CIDER FEST!
Bring your tools for sharpening
Bring your appetite for tasting
Bring your wallet for homemade goodies

In cool climates, powdery mildew typically shows up one month after bud break – approx. May 30. Weather During Critical Epidemiological Periods and Subsequent Severity of Powdery Mildew on Grape Berries. Plant Disease 100:116-124.   Moyer, M.M., D.M. Gadoury, W.F. Wilcox, and R.C. Seem. 2016.

control

Proper pruning, including fruit-zone leaf removal and shoot thinning, to facilitate air circulation and sun light penetration is critical to aid in the control of powdery mildew. UV exposure and air circulation are both effective against this fungal problem.

Sadly, our most mature set of three vines rest along the sound wall where air circulation is compromised.

Michelle referred to a study by Matthew DeBacco (2011)  wherein compost tea and milk spray were used to combat powdery mildew.

Well! These materials were easy to find and certainly organic so we began our own experiment. The left vine we treated with neem oil, the middle was the control where we did nothing and the right vine received powdered milk spray (1/4 C non-fat dry milk, 1-T baking soda and a few drops of dishwashing soap to a gallon of water.)

We were not absolutely consistent in our applications but we tried to spray about every week to 10 days.

pow. milk

Our results (see photos) were convincing; the powdery milk spray was the most effective. All clusters dropped on the control and all but one on the vine sprayed with neem oil but we did have clusters ripen completely on the milk treated vine.

Next year we plan again to spray using an improved milk recipe per the studies we’ve read. We’ll use a backpack sprayer to make the process more efficient. We’ll also prune more effectively in February and remove fruit zone leaves a bit earlier than we did this year. We may try compost tea as a test spray against the milk spray. However, making the tea every other week is quite a process so we shall see.

 

Nancy

P.S. On a recent visit to Carnation Farms, the garden supervisor mentioned that she has had luck treating basil with powdered milk spray.

More reading: Crisp P, Wicks TJ, Troup G, Scott ES (2006) Mode of action of milk and whey in the control of grapevine powdery mildew. Australasian Plant Pathology 35, 487–493. http://www.publish.csiro.au/ap/ExportCitation/AP06052

Tulle – A Cool Tool

September 3, 2018

Stretching the parameters of our climate is part of gardening. We add row covers or netting to keep out a pest or alter sunlight transmission. But it’s not that simple is it? These tools can affect soil and air temperature, humidity, wind, light penetration, pollination, and productivity. Did you know red shade cloth can increase productivity of tomatoes.

For example, installing a row cover with a mesh size to keep the white fly off your Brussels sprouts will most assuredly cause a decrease in sunlight and wind, and a mid-day increase in humidity and air and soil temperature.

The impacts that row covers and netting have on plants are significant. Seeds need a certain soil temperature to germinate successfully(1). Better ventilation helps reduce air temperature and humidity and improves the evapotranspiration process for crops (plants sweat through their leaves).

In short, well, there is no “in short” to this topic. It’s complex. Try figuring out how to relate the Frazier measurement of air permeability to the discharge coefficient. Note the gaps in my chart!

Sun, Sep 9, 10-11, Intro to Qi Gong
Sun, Sep 16, 2-4, Work Party
Sat, Oct 6, 2-5, Cider Fest!
Sun Oct 21, 2-4, Work Party

I had to call an engineer, who settled the air permeability issue for me. “Just take your shop vac, put the hose on the other end so it blows out and hold the fabric up near your face. You will feel which fabric has better permeability.”

By the way, if you get stubborn and want to figure this stuff out, know that there is a pretty good relationship, with very thin fabrics, between porosity and air permeability. And, there is a pretty good relationship between water permeability and air permeability. Try putting the fabric in your coffee filter holder, run water through and time each fabric.

For an overview, here’s a link to a general article about agrotextiles from Textile World, http://www.textileworld.com/textile-world/nonwovens-technical-textiles/2005/09/agrotextiles-a-growing-field/ However, there is nothing in the article about Tulle. Tulle?

Rhode Is Sch of Design

Netting is a nylon fabric in which the warp (vertical lines) and weft (horizontal lines) yarns are looped or knotted to create open spaces in the fabric. Tulle is essentially a special type of netting with a lower denier, which means the individual fibers are finer. Tulle is lighter than netting, and the spaces between threads are smaller.

You can Google Tulle and turn up tutu designs but, if you want to know about the fabric characteristics you end up reading medical studies. You can use it to repair a hernia!

I decided on Tulle for my Brussels sprouts this year. Why? Because it comes in lavender!

Important note – Row covers or netting need to be removed from some plants to allow for pollination. Most vegetables that produce flowers before they make a crop, such as squash, cucumbers, tomatoes and peppers, require visits from insects. Root crops and leafy greens need no pollination, so they can live under covers until they are ready to pick.

Ruth

(1) Cold Crop Vegetables – Tagawa Gardens

In Praise of the Power of Pollinators

August 5, 2018

Gardening is hard work. It is rewarding, but the task is never over. That’s why we should always remember to give thanks to all the help we get at the orchard. Our wonderful volunteers help keep us going. But our hardest workers are some of our smallest. Without our pollinators, we wouldn’t be able to enjoy the bounty from our gardens. We rely on plants to power us, and our plants rely on them. They help keep our flowers, fruits, and vegetables strong.

Christine Ranegger came out to the orchard on July 21st to teach us about our six-legged volunteers. Christine is a neighborhood captain with the Puget Sound Beekeepers Association, and her expertise and passion for the bees is clear. I and the other lucky attendees learned a lot.

Sun, Aug 19, 2-4, Work Party
Sat, Sep 1, 10-noon, Work Party
Sun Sep 9, 10-11, Intro to Qi Gong
Sun, Sep 16, 2-4, Work Party

We learned about three different types of bees from our capable instructor. One of the most surprising facts I took away was that bumblebees and honey bees were two entirely different species! The honey bee is the bee most of us think of. Large nests, bee dances, and a painful stinger left in your skin are all hallmarks of the honey bee. Honey bees also have a further range than bumblebees, sometimes traveling two miles away from the hive in search of nectar. While bumblebees create nests and create complex social structures, they don’t have some of the same interesting behaviors and dynamics as honey bees. When a new honey bee queen is born, the old queen peacefully leaves the hive with a set of worker bees. If you ever see a swarm of bees, don’t hesitate to contact your local bee-keeping association or fire department! The bees might find a home with a local beekeeper, instead of in the siding of a home.

We also learned about mason bees. These bees prefer solitude, and typically range only a couple of hundred feet from their home base. They like to nest in blocks with tubular holes in them. The females are usually placed near the back of the hole, while the male cocoons are placed near the front. This strategy allows the males to hatch first and protects the valuable, pollinating female cocoons from hungry woodpeckers!

The weather was perfect, and I left inspired to seek out my apian friends the next time I walked past a lavender bush. It didn’t hurt that I was able to walk away with a jar of Christine’s delicious honey!

Max