Susan is also blogging at GardenRant.New Hort Research that Gardeners Can Use: March '09 Roundup
By Jeff Gillman
Jeff Gillman, associate professor of horticulture at the University of Minnesota, writes quarterly reports of horticultural research that gardeners can use for this website.
Do you remember taking tests in school? Remember how anxious you were to confer with your friends after the test to see if they got the same answers you did. This may shake your view of scientists a little, but that’s kind of what it’s like with scientists when new papers come out on topics that they’ve already written about or researched. We’re always taught that scientists are cool, cautious individuals who value objectivity above all things. We certainly try, but speaking for myself I can tell you that we’re also human and so are prone to human reactions. When a new paper is published on something that I’ve worked on I get anxious before I read it because I hope these new results agree with my own. And, while I go out of my way to present articles which reach conclusions different than my own, there’s something gratifying about reading a paper where other researchers have independently reached the same conclusions that I have. It’s kinda like being able to say “I told you so”. The reason I mention this is that the first two articles I’ve decided to present here both gave me that little “I told you so” feeling.
1. Compost Tea? Not so much
Those of you who have read my books or my posts here know I’m not the biggest fan of compost tea, and the first article helps to justify my skepticism. This article examined the effects of two compost teas (a homemade aerobically produced manure tea and the commercially available Efficient Microbes) on collard and spinach growth and the result was that, in general, these teas did not increase the yield of these plants. (There was one treatment where non-organic methods were used in combination with the commercial tea and showed a slight increase in yield, but this was only true in one of two years and was considered statistically insignificant).
Furthermore, this research looked at whether compost tea increased microbial activity in the soil and found that it didn’t. I’m always a little surprised when people think that adding microbes to the soil will increase microbe activity. It really shouldn’t. Think of a thousand people taken from Boston and suddenly dropped into the middle of the Mojave Desert. How many would remain after two weeks? Living beings, whether human or microbial, will only proliferate where conditions are good for them to live.
2. Mycorrhizal products? Save your money
A commenter to my last research update asked about mycorrhizae and whether it’s a good idea to add them to your plants or soil. I was concerned that I’d need to look up some old articles and post those until last week when this shiny new article about mycorrhizae found its way into my mailbox. In this article researchers applied commercial mycorrhizal products (9 of them!) to various plants and discovered that, in most cases, these products do not increase the mycorrhizal colonization of plants they’re applied to. (An insignificant 5% increase was about as good as it got). Mycorrhizae are everywhere and so I’m not sure there’s a good reason to purchase them from a commercial source.
3. Butterflies are choosy!
If you’re planning on planting Zinnias, here’s a neat little article you’ll appreciate. Butterflies preferred the cultivar ‘Lilliput’ better than 2:1 over any other cultivar of Zinnia tested. (Other cultivars tested included ‘Oklahoma’, ‘State Fair’, and Pinwheel’.)
4. What landscaping is worth
Readers probably realize that nice landscaping can help sell your home, but exactly how much extra is this nice landscaping worth to buyers? Well, 75 homes in Lubbock, Texas were examined to determine how much and it turns out that a high quality landscape increases the sales price by 5.7 percent, compared to average landscapes. Then comparing average landscapes with excellent ones, the difference in sale price is a whopping 10.8 %. Furthermore, the authors calculate that every $1.00 spent on the landscape returns $1.35. I’m obviously investing in the wrong place.
5. Balled, burlapped and busted?
If you plant balled-and-burlapped (B&B) trees, a new study shows that handling and transporting them in that form is detrimental to their growth. It also seems to contradict recent statements from some quarters that it isn’t important to keep the ball of soil around those B&B trees intact. As a side note, last spring I tried planting B&B trees after very carefully washing off the root ball and of the five trees I treated this way, all died. The five trees I planted using more standard practices all lived.
6. Plants are powerful things
If you’re visiting this blog then you know the power of plants to heal. Nonetheless, here is a little article that I hope will brighten your day. Patients that underwent surgical procedures and were placed into rooms with plants and flowers had shorter hospital stays, less pain, fatigue and anxiety, and liked their rooms better than those who didn’t have plants in their room. File this under “who would’ve guessed.”
Citations
1. Knewtson, S.J.B., J.J. Griffin, and E.E. Carey. 2009. Application of two microbial teas did not affect collard or spinach yield. HortScience 44(1):73-78.
2. Wiseman, P.E., K.H. Colvin, and C.E. Wells. 2009. Performance of mycorrhizal products marketed for woody landscape plants. Journal of Environmental Horticulture 27(1):41-50.
3. Yeargan, K.V. and S.M. Colvin. 2009. Butterfly feeding preference for four zinnia cultivars. Journal of Environmental Horticulture 27(1):37-41.
4.Stigarll, A. and E. Elam. 2009. Impact of improved landscape quality and tree cover on the price of single-family homes. Journal of Environmental Horticulture 27(1):24-30.
5. Koeser, A.K., J.R. Stewart, G.A. Bollero, D.G. Bullock, and D.K. Struve. 2009. Impacts of handling and transport on the growth and survival of balled-and-burlapped trees. HortScience 44(1):53-58.
6. Park, S.H. and R.H. Mattson. 2009. Therapeutic influences of plants in hospital rooms on surgical recovery. HortScience 44(1):102-105.
Jeff Gillman is an associate professor of horticulture at the University of Minnesota. He's also the author of two books, "The Truth About Garden Remedies" and "The Truth About Organic Gardening" (Timber Press). Marigold photo from Blossom Creek Farm. Tree photo by SSTUDIO.