Robots in the Nursery

Back in my day, of horticulture school and nursery internships, we did this work by hand.  At the end of the day, resetting rows of 3 and 5-gallon boxwood, I would crawl out to my car and drive home, then crab crawl into the house and ice my back.  One Saturday morning, after a week of moving hundreds of nursery containers and doing hours of hand-weeding in the shadehouse, my back spasmed in the Safeway parking lot and I lied on the asphalt for a spell thinking about my future.  Being a grower was not in the cards I surmised, and I turned my sights from production horticulture to production problem solving.

In the meantime, along came Harvest Automation.  These little guys are so cool – efficient, precise, and tireless.  Their backs don’t spasm, they don’t complain, they space rows like a boss.


Robots in the Nursery from Vox Hortus on Vimeo.


This Week is Eating Me Alive

I’m in a first week flurry of classes and labs and club meetings and searching for misplaced things.

Something new is coming to the blog this week, in honor of fall and the Liquidambar which are just beginning to turn.

Wait until you see it, and you will know how committed I am to providing you with a quality blog experience.

Horticulture Booming in Oregon

Oregonians spend almost 1 billion dollars on their gardens

COTTAGE GROVE – More and more Oregonians are looking no further than their own backyard for a favorite hobby. The state’s horticulture industry climbed ten percent last year alone, making it Oregon’s largest agricultural commodity.

At the 5th annual “Gathering of Gardeners” event, the Village Green Resort in Cottage was all in bloom. Cindee Eichengreen, the Moonstones Director of Horticulture says, “Our theme here is to motivate, educate and inspire gardeners of all ages and all stages including gardeners who have never gardened before.”

Events like these are drawing more and more people each year all throughout Oregon making our state one of the best for horticulture. Here in Lane County, Eichengreen says, “It hasn’t been too hot or too cold. We’ve had just the right amount of rain.”

Gardening in the Northwest is so popular nearly one billion dollars was spent on the hobby in 2006 alone. That’s record breaking sales for the 16th consecutive year.

Organizers say you don’t need to have a green thumb to make a successful garden. “Some of the best gardeners on my team are people who have never gardened before,” says Eichengreen.

The gardening industry is a rising star in Oregon. Industries like cattle, grass seed and hay used to be market leaders but now the gardening industry has grabbed 21 percent of the agriculture market.

Oregon’s top areas for horticulture production are Marion, Washington, Clackamas, and Yamhill counties. They account for 81 percent of all sales statewide.


Oregon is #3 in nursery stock production nationwide, after California and Florida.

Homegrown, Local and In-Season: the dark side

This year, I’ve eaten much more in line with the above sentiment but have been chagrined to discover that it’s something of a challenge – and not in the way I expected.

In early summer, the strawberries were staggered and we had several handfuls a day for about a month. The birds helped themselves, and still we had plenty. They were fabulous on cereal or directly from the plants.

The cherries were next, and it was a so-so year for them. We had plenty for us and shared quite a few. They weren’t as good as previous years and only one of the two trees really bore a good amount of fruit. The dogs ate whatever fell to the ground.

A month or so ago, we ate blueberries by the pound as our 4 bushes all came into fruit at the same time. This wasn’t even a good year for blueberries. The flowers bloomed when it was still too cold and wet for the bees that pollinate them, so the harvest was sparse compared to previous years. Nevertheless, we were awash in Vaccinium for two solid weeks.

Three weeks ago, the peach tree simultaneously produced about 25# of the most delicious, incredible peaches I have ever had in my entire life. The tree looks like a decrepit twig, but I won’t cut it down because, really, fruit like that? Nectar of the gods. Sadly, much of it went to waste because a) there was no way I was sharing, b) my back was out and I couldn’t can it, and c) I can only eat so much stone fruit in a day. Live and learn.

The pear tree is bearing a good crop for the first time this year. The dogs are beside themselves and I keep finding stashed pears in the house. Yesterday, the lab brought me one and laid it on my pillow while I was still asleep. As soon as I made the sounds of waking up, she changed her mind and jumped up and ate it. I haven’t tried any of them myself yet; they’re just creeping up on ripeness.

Blackberries are also ready, so ready in fact that the smell of them is everywhere in the late afternoon.

Apples are looking good. I’ve thinned the crop a bit so the fruit can develop a little larger. As I recall, these are baking apples – not that it stops the dogs who will even eat crabapples, though they make faces.

Zucchini. Here’s where it gets ugly. The neighbor has brought over probably about 30# of zucchini in the past few weeks, as well as green beans, summer squash, and cucumbers. It was lovely and rustic the first time, but now my tiny kitchen is looking like a commercial set up with pans and colanders and knives and garlic strewn about. Both sides of a double sink are overflowing with zucchini, there’s more I haven’t unloaded yet, and I’ve already roasted two pans worth.

I think tonight I’ll wait in the dark on the porch with my shotgun. The freezer is nearly full and I’m wising up to the midnight zucchini drops.

What I didn’t know about seasonal eating is that it’s marked by periods of tiresome repetition: a few weeks of eating more of something you love than you really wanted, particularly if you plan and continuing to love it. Even blueberries get old after ten days.

Arabidopsis Thwarts Land Mines

A Copenhagen biotech firm has modified a common Arabidopsis to detect nitrogen dioxide and express red leaves instead of green in its presence.  Over 100 million landmines worldwide are a danger to humans and animals and leave prime agricultural land fallow.  Now the nitrogen dioxide that they outgas can be detected by this lowly thale-cress which is seeded by air.  When the plants grow and express the red color, mine removal teams know exactly where to direct their efforts.  The red color will also serve as a warning to passersby who can avoid stepping on the mines.  Very exciting news.

 Overview from the Landmine Survivors Network here.

Literature Review: Biennial Bearing

Dennis, Frank G. and Neilsen, John C. 1999. Physiological Factors Affecting Biennial Bearing in Tree Fruit: The Role of Seeds in Apple. HortTechnology 9(3): 317-322.

This article, rather than a publication of new research, is a review of the existing research to date on the biennial bearing patterns of apples and pears. Research has been aimed at discovering why some varieties exhibit biennial, or every other year, bearing: during “on” years, there is a full fruit crop but floral initiation for the following growing season is inhibited; during “off” years, there is no fruit crop as a result of the previous season’s failure to initiate flowers, but floral initiation proceeds normally during the current year for a full fruit crop the following year, and so on. The idea that flowering inhibition is a result of nutrient partitioning to developing fruit rather than initiating flowers is set aside in favor of two hypotheses that link developing seed-bearing fruit to inhibition of floral initiation.


Chronologically, the referenced research is as follows: in 1918, Kraus and Kraybill’s work with carbohydrates and nitrogen concentrations in Lycopersicon suggested that nutrient aviailability was a factor in flowering, and subsequent studies probed this hypothesis with inconclusive results. Roberts ‘1920 study suggested that “flowering is greatest when shoot length is intermediate,” which was untrue for strongly biennial varieties. Chan and Cain (1967) showed that it was the developing seeded fruit that was inhibitory towards floral initiation unless the flowers/fruit were removed within a few weeks of bloom. In 1996, bourse shoot length was revisited and the Michigan grown, commercial, biennial and seeded ‘Paulared’ was evaluated. The authors reported inconsistent effects of shoot length on flowering, and in this particular variety, floral inhibition was also not consistently correlated with developing fruit. However, it is accepted that in general, parthenocarpic varieties exhibit floral initiation inhibition in the presence of seeded fruit. Two hypotheses roughly fit these existing data and are good candidates for further study: the export of biochemical inhibitors from developing fruit, and priority for florigen, the hypothetical floral promoting hormone.


For the first hypothesis, Luckwill (1969) demonstrated that “seeds contain[ed] relatively high concentrations of gibberellins,” and he proposed diffusion of GAs into the bourse shoot, which was supported by higher concentrations in the bourse shoot tissue adjacent to developing seed. This would explain the apparent relationship advanced by Roberts between floral initiation and shoot length (in some varieties). Though this conclusion is widely accepted, it is not equivocally supported by subsequent research. In fact, there is a disconnect between increased GA concentration in shoots and unexpected lower concentration of GA in developing seeds. In some cases, the GA exudates in the bourse shoot were in another form of GA (GA4) which is sometimes floral inducing. How GA is distributed or diffused between seeds and bourse tissue remains unclear even after studies where GA was radiolabeled for tracking. Green (1987) showed that less than 0.01% of labeled GA was transported, even when accompanied by hypothetical biochemical precursors. Subsequent studies produced similarly small percentages of transport, though there was relatively more GA diffusion from seeded than unseeded varieties, and GA4 levels were found to be lesser during floral initiation.


Additional factors may play significant roles. Callejas and Bangerth (1997) suggested that IAA might be a “secondary messenger in the inhibition of flowering,” but no appreciable differences in IAA levels in tissues were demonstrated between annual and biennial varieties. Additionally, naphthaleneacetic acid (NAA), a thinning agent that also has been shown to stimulate flowering, could possibly produce results that mimic floral initiation at fruit removal. Neither substance’s role is well understood at this time.


The second hypothesis is based on Ryogo’s hypothesis that “seeds have priority for florigen,” referring to the hypothetical hormone thought to promote flower induction (1988). In this scenario, instead of carbohydrate partitioninig or prioritizing, the substance that reproductive tissues might be vying for is florigen, which is thought to be produced by leaves and available relative to leaf area. Adequately long bourse shoot length and adequate leaf area could diffuse enough florigen to make flower initiation possible even with adjacent development of seeded fruit, which fits with Roberts’ findings. The authors also note that this hypothesis “might explain the failure of seeded ‘Bartlett’ pear fruit to prevent flowering in California, where water and sunlight are abundant and growth is vigorous.” This supports the idea that increased leaf area would result in increased concentrations of its assimilate, florigen – enough for seeded fruit development and floral initiation to be concurrent. Substituting “florigen” for “nutrients” in the previous hypothesis of carbohydrate partitioning (Kraus & Kraybill) would corroborate those findings.


At this stage of researching the physiology of biennial bearing, it isn’t clear what the research question is or what mechanism or substance is being sought. In discussing the inhibitor export theory and IAA/NAA effects, the authors acknowledge that inconclusivity may reflect the limits of technology at the time of these referenced studies. Possibly none of the existing scenarios is a good approximation. Luckwill has posited that a balance of phytohormones involving cytokinins may be play a role, as might antagonistic reactions between substances. Practically speaking, complex and as yet understood chemical balances and relationships are certainly germane. Additionally, this article does not discuss other factors outside the scope of completed research, such as why some trees can be induced to biennial bearing after a hard frost. There have been insufficient comparisons among species and cultivars, an aspect of the research that may have to wait until a firmer hypothesis is in place.


In conclusion, what is known with some confidence is that “seeded fruit of biennial cultivars of apple and pear [does] inhibit flowering, whereas seedless [fruit] do not,” and for now, the “effect of the seeds declines as bourse shoot length and/or leaf surface per bourse increases.” This article is a good starting off point for future research, provided inquirers agreed with these hypotheses, but it also shows that previous studies attempting to answer the same question have addressed it in very different ways. As technology and funding are available, it might be possible to answer the questions of inhibitor export and florigen priority.