Author Archives: Ruth

What’s in the Air is Fair

January 12, 2019

Is it risky to eat food grown next to the Freeway? Orchard visitors sometimes ask this question. It is an especially interesting question to me, an Environmental Protection Agency retiree and air quality specialist.

The two principle ways food can become contaminated from environmental pollutants are through soil and air. In urban areas, lead is the soil pollutant of greatest concern. In 2010, before we started growing food at Freeway Estates, we tested the soil and found low lead levels (13 ppm).

How bad is our air? Even though levels of fine particulate pollution have risen in recent summers because of wild fire smoke, Seattle’s air quality is better than most major cities in the United States. Still, I questioned whether air quality at the orchard, with its proximity to I-5, is worse than other places in Seattle. A recent University of Washington study on neighborhood-scale air quality offered a partial answer. When Justin sent us an email about this study, I quickly volunteered my yard, located one block from the orchard. Technicians from UW placed an air quality monitor in our yard in the summer of 2017 and spring of 2018. The 2017 monitoring included a period of high wild fire smoke. The machine measured particulate matter, nitrogen dioxide, ozone, and carbon monoxide. Levels found in our yard were not high compared to levels found elsewhere in Seattle.

Sun Jan 20, 2-4, Work Party
Sat Feb 16, 1-3, Tree Pruning Class
Sun Feb 17, 2-4, Work Party
Sun Mar 17, 2-4, Work Party

But, can fruits and vegetables absorb air contaminants? I have found little research on this question. A 2017 study in Sao Paulo Brazil looked at polycyclic aromatic hydrocarbons (PAHs), a ubiquitous air pollutant from the burning of fossil fuels and biomass. The study found no significant PAH concentrations in spinach and collard greens grown in the presence of high levels of PAH. It seems possible, however, that air contaminants can settle on the surface of garden produce and become available to us if we eat them without washing. So, it’s a good idea to wash even organically grown fruits and vegetables.

While I did not find evidence that we consume air pollutants when we eat food grown in urban gardens, there is plenty of evidence that consuming fruits and vegetables is good for our health. In fact, the antioxidants and other phytochemicals in fresh produce may help protect us from the harmful effects of air pollution. So, I’ll continue to enjoy the super-fresh produce from our FECO garden plot, appreciating the healthful properties and great taste – after I wash them.

Nancy

Fall Fruit Tree Follow-up

November 30, 2018

Fall is a fine time to do investigative work in the orchard and plan for winter or spring pest management.

Confirming that our Harrow Delight pear problem was Pear Trellis Rust (Gymnosporangium sabinae) was an excellent warm-up exercise, since the blemishes on the leaves are so clearly identifiable. I made a leaf infusion and put a drop under the microscope. There wasn’t much else to see but for the spores of this particular fungal problem. Confirmed.

Another set of eyes is so valuable when reviewing the status of the plants. We warmly welcome Allison, a new volunteer, who joined Sue and I last week as we continued our review of the fruit trees and other fruit-bearing perennials.

The three of us started with the Izu Persimmon and worked through the checklist:

  • Add Tanglefoot to trunk to dissuade the winter moth from laying eggs
  • Clear debris from around the root crown
  • Make sure staking materials and any plant ID tags are not choking a branch or harboring pests
  • Look for eggs on all surfaces
  • Review the new flowering buds for health
  • Prepare a leaf infusion if a fungal disease is suspected
  • Cut a twig and drop the end in water to check for ooze if a bacterial problem is suspected
  • Identify bamboo watering holes with survey tape to minimize tripping hazards
  • Add compost and mowed leaves, and consider the timing for full sheet mulching
  • Look for anything unusual.
Sun. Dec 16, 2-4, Work Party
Sun. Jan 20, 2-4, Work Party
Sat. Feb 16, 1-3, Tree Pruning Class
Sun. Feb 17, 2-4, Work Party

There was little to study on the Izu; the only problem it had was too many fruit. Of the 24 fruit it presented to us, we only allowed 7 to remain on the tree. It will need time to build a stronger scaffold to support more fruit.

We moved on to the Early Fuji for review. The new buds looked cheerful but the Fuji suffered from scab this year. After bloom, we had netted it with bee netting in order to keep the coddling moth at bay. We might have replaced coddling moth damage with scab damage! The apples were still edible and many were pristine enough for the food bank. But, we won’t net next year, in order to assess whether the tree will be healthier with improved air circulation.

The scab (Venturia inaequalis)  (photo) was also a pretty easy diagnosis but it can be confused with sawfly damage. Again, a leaf infusion confirmed the presence of many of the shoe-shaped spores associated with apple scab.

We noticed two male and one female winter moth caught in the Tanglefoot band around the lower part of the tree trunk. Since the moth activity is just past it’s peak, we set about looking for eggs and anything else that might pose a risk to our tree.

We didn’t find eggs but Sue was standing at exactly the correct spot to be staring right at the tiny protective covering of a scale insect. Good eye Sue! We were not sure of the scale type so we looked up its characteristics to confirm. I also pulled one apart and set it under the microscope to look at the multitude of white eggs. (A compound microscope can be crudely fashioned into a dissecting one with an extra light source.) We agreed it was Lecanium Scale (Parthenolecanium corni) and we will pinch those little bumps off the trees as we see them.

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Next week we review the Mirabelle Plum and its multiple problems, makes notes, develop our plans for that tree in the coming year and, hopefully, find something else interesting to put under the magnifying glass.

Ruth

It’s A Game Of Mistakes

October 20, 2018

Why didn’t soccer coaches ever have anything positive to say at halftime? Because they had just watched 45 minutes of errors. Even the pros only complete 57% of their passes in the final third of the field. I often feel this way about gardening; it’s a game of mistakes.

First was my failure to outwit the winter moth. The female does not fly. She has to crawl up the fruit tree to lay her eggs, from which, larvae emerge and eat the fruit tree blooms. I smeared Tanglefoot on the trunks to stop her in her tracks. Problem was, I put it on too late. I thought I had until mid-November but, not so. Not only did we battle with the winter moth larvae this spring but also the oblique-banded leaf roller larvae showed up – a more difficult opponent. I will double my efforts to come up with a better strategy this winter.

Just look at this little devil – the larvae of the strawberry root weevil. Sometimes there were two of them inside the root, in total cooperation. I was pressing my luck hanging on to those wonderful Glooscap (Canadian) berries, which I had planted in 2011! This year they were still sweet as ever but not productive. It’s no wonder. I should have paid heed when the pros told me to keep strawberry plants only a few years.

The elderberry produced quite a bit of fruit, bless its lil ole heart, in spite of the fact that it was a sufferin’. I pruned dead branches all summer. Finally, I sat and studied it a bit. Someone was making tunnels through the bark and into the trunk. I peeled back some flaky bark and watched as the following scampered back to darkness: black ants, red ants, tiny gray bugs with antennae, a slender shiny black insect that jumped, a little red mite. Actually, I have a feeling all of these critters were just using the network created by someone else. I won’t know until dormant season when I will have to do some vicious pruning. Observation is king in gardening!

Sun. Oct 21, 2-4, work party
Sun. Nov 18, 2-4 work party
Sun. Dec 16, 2-4 work party
Bring your wallet for homemade goodies

Nancy also had growing pains. It’s a snap to grow grape plants if all you want are vines. To get fruit, you have to prune properly. Nancy thought she could choose between cane pruning and spur pruning so she developed some of each. Wrong. The take-away from a WSU pruning class was that, in the maritime NW, spur pruning reduces the number of fruit-bearing buds. So, this winter she will have to rework the vines and train them for long-term cane pruning.

Then there’s summer pruning. She thought all you had to do was take out excess growth. She took another class. Wrong. Wow! It’s so much more complicated. Essentially, you need to do three things: mark the shoots that will become next year’s canes, remove some but not all of the non-fruit bearing shoots, train but don’t tip the fruit bearing shoots. Training means get them up off the ground and onto the trellis, but don’t snip off the terminal bud.

Not to mention the continuing saga of failed pickling cukes, the appetite of the rats, the disruption from the squirrels, and the off-leash dogs. All this to deal with and now … the bunnies are coming!

Ruth