Talkin’ Tomatoes

April 16, 2019

I am a tomato addict. One of my favorite memories is arriving in rural southwest Ohio at 6 am after driving straight through from the west coast. We stopped for breakfast at a coffee shop and were served a plate of eggs and fresh picked tomatoes, grown by the owner in his back yard. It’s nearly impossible to find that level of deliciousness in grocery stores, where tomatoes are bred for color rather than flavor. (To find out why this happened check out Flavor Is Price of Scarlet Hue of Tomatoes, Study Finds, New York Times, 2012.)

I love tomatoes that taste good, which is why I like to grow them. I’ve been growing as many as I can for a few years now and learned a few things along the way. There are numerous articles on how to grow tomatoes but it seems that few ever read these. This may be due to the terminology. The minute I ask someone if they are growing Determinant or Indeterminant tomatoes, their eyes gloss over and they start looking for a quick escape. Knowing these basics can result in a less frustrating and possibly cheaper tomato crop. Vegetable starts are already showing up at nurseries and plant sales are right around the corner so – know what you want BEFORE you shop!

Sun Apr 21, 2-4, Work Party
(deviled egg hunt)

Sat May 4, 10-12, Work Party
Sun May 19, 2-4, Work Party

DETERMINANT tomatoes grow like small shrubs or bushes. If you are growing in containers and don’t have huge tomato cages, or aren’t into constructing large trellises, these are the plants to look for. They stay more compact and produce a limited (determinant) number of flowers. The fruit ripens over a few weeks and then they are done. DON’T PRUNE THESE BABIES (except for low foliage that touches the soil) or you will lose some of the fruit. Look for varieties that ripen in 80 days or less.

INTERDETERMINANT tomatoes are vines that keep growing and producing flowers and fruit until the first frost or disease hits. If you do nothing, they will become a tangled mess, so be ready to trellis. Not everyone believes in pruning tomatoes, but I prefer to prune them to 2 or 3 main stems that are trained to grow up a trellis and I remove the suckers at least during the first month after they get planted in the ground. “Suckers” are new vines that start to grow from the point where the leaf meets the main stem. Some varieties are not as vigorous, so less pruning may result in more fruit.

SEMI-DETERMINANT. These tomatoes are bushier than indeterminants but will keep producing for a longer time than determinant plants will. Pruning may not be necessary at all unless you want to promote good airflow by removing some of first suckers that appear low on the plant. They are often more compact and make good choices for containers.

Volunteer tomato-growing enthusiasts:
If you like to grow lots of tomatoes (like I do!) and have the space and lots of sun, indeterminant tomatoes are the way to go. But for those of us who have a sunny porch with space for a container or two, tomato breeders are working on developing better tasting compact varieties. Volunteer tomato growing enthusiasts have developed at least 40 new varieties for The Dwarf Tomato Project and are working with 3 seed companies to release them to the public. Urban tomato growers rejoice!

Tomatoes aren’t that hard to grow, but there’s plenty more to learn and the best way to learn is by giving it a try. There are lots of great resources out there to help you along the way. We plan to grow lots of tomatoes once again for the University District food bank at Freeway Estates Community Orchard. Stop by! If I’m around, I’ll be happy to talk tomatoes with you!

Sue Hartman

Plant Pathogens – Pasteurize? Sterilize? Sanitize? Boil Everything!

March 26, 2019

Recently, I was watching someone rinse a plastic polyethylene plant-potting container in a Brown Rotbleach solution for reuse. I was pretty sure that pot needed to be thoroughly rinsed of organic matter prior to the bleach rinse.

The observation made me think of several reasons why a gardener needs to know how kill plant pathogenic microbes, e.g., effectiveness of our thermal composting process, best product to spray on our pruning shears or, preparation of a previously purposed plastic pot for propagation.

I tried and failed to make a helpful chart. It proved far too difficult, due to so many factors to consider:

varied expressions of quantities
different types of substrates and their porosity
amount of contact time needed
type of organism and state of organism
health hazards
the level of disinfectant desired
shelf life of product
humidity in relation to temperature
corrosiveness
cost of product
where the organism lies and whether you can even get at the bugger

Method

 

Botrytis cinerea (gray mold-fungal) Nectria galligena (apple canker) Weed seed

(sow thistle)

Verticillium dahliae (Verticillium wilt)

 

Pseudomonas syringae pv. tomato (Bacterial speck)
0°F yawn
165°F Dead 1 hr Dead 1 hr
5% sodium hypochlorite (bleach) sol. 2g/liter 20 hr LD90
4%v/v iso. alcohol effective
.3% iodine solution 93% dead 93% dead
Quaternary ammonium 4g/liter 20 hr LD90

Heat destroys microbes best and heat with humidity is even better. However, except during our thermal composting process, heating to 149F for two hours is not practical. As such, I tried to get some answers about products that are available and familiar.

Sat, Apr 6, 10-12, Work Party
Sun Apr 21, 2-4, Work Party
Sat May 4, 10-12, Work Party
Sun May 19, 2-4, Work Party

Let’s start with bleach. Sodium hypochlorite is very reactive, affected by surface contamination from organic matter and it’s irritating to use. It’s difficult to know what dose to use and, at the concentrations that many people use, it leaves a residue on the surface. (1000 ppm will destroy all microbial pathogens but for the tough resting spores. Using household bleach (5.25% sodium hypochlorite), the dilution would be 1:50 or 5T per gallon.)

Ethanol (think Everclear) can kill most organisms but it is highly flammable and evaporates quickly. It dries out the organism (which is why the similar product, isopropyl alcohol, is better as a disinfectant for the skin). Alcohols reportedly won’t kill some spores and they harden rubber and some plastics on tools.

I could not get a clear idea whether hydrogen peroxide is a good pathogen hunter. Articles refer to its effectiveness, especially on inanimate surfaces, but indicate that hydrogen dioxide is a superior disinfectant on plant production surfaces.

Quaternary ammonium chloride. Hmm. There is a lot of controversy about Quats and they are reported to be not always effective against the tough customer – the fungal resting spores.

This brings me to a possible unsung hero – iodine. Remember when you went camping where the water was bad. You mixed the two tablets in water and waited. That second tablet helps with the discoloring and the taste and also is a solubilizing agent. One potential downside is shelf life – about five years.

A flameless loop sterilizer might be the ultimate tool but not readily available and you would need a power source. (We will leave out solarization, which, for the time being anyway, might be challenging in Western Washington.)

This study is way more complex that I could have ever imagined. There is no one size fits all solution. Shown here is a popular chart from two State of Washington professors (who are also fine authors of plant pathology books).

Good reads:
Investigation on the fungitoxic effect of an iodine solution on three plant pathogens in vitro. Bengt Boysen.
Bachelor project in the Danish-Swedish Horticulture programme
2004-1 (ISSN 1652-1579)

Time and Temperature Requirements for Weed Seed Thermal Death
Ruth M. Dahlquist, Timothy S. Prather, and James J. Stapleton
Weed Science 2007 55:619–625

Soil Solarization and Thermal Death: A Logarithmic Relationship Between Time and Temperature for Four Soilborne Plant Pathogens.
G.S. Pullman, J.E. DeVay and R.H. Garber
American Phytopathological Society, Vol 71, No. 9, 1981 p 959

Temperatures Necessary to Kill Fungi in Wood
USDA Technical Note 259, Forest Products Lab Feb 1956

Safe Procurement and Production Manual A Systems Approach for the Production of Healthy Nursery Stock
Griesbach J., Parke, J.L., Oregon Association of Nurseries, January 2012
https://www.researchgate.net/publication/282649506

Dose Curves of Disinfectants Applied to Plant Production Surfaces to Control Botrytis cinerea
W.E. Copes, Plant Disease-American Phytopathological Society, May 2004

Chemical Disinfectants
https://www.cdc.gov/infectioncontrol/guidelines/disinfection/disinfection-methods/chemical.html

Quaternary Ammonium Compounds
Quaternary ammonium compounds are the most commonly employed broad-spectrum hard surface disinfectants employed in animal research facilities.
From: Laboratory Animal Medicine (Third Edition), 2015
https://www.sciencedirect.com/topics/neuroscience/quaternary-ammonium-compounds

EPA Hard Surface Disinfectants
https://www.education.nh.gov/instruction/school_health/documents/disinfectants.pdf

Ruth

Get To The Root Of The Matter

February 4, 2019

Last week Sue helped us plan the vegetables for the year. We were thinking of what to plant near the far north olla and we got out our photos of plant root lengths from the summer.

The olla best serves a plant with a deeper root system. (See Water Conservation page on Ollas.) We decided peas would be a good choice.

The plants can teach us so much. We dig up some of the roots to assess for health and to measure length.

Sat, Feb 16, 1-3, Pruning Class
Sun Feb 17, 2-4, Work Party
Sun Mar 17, 2-4, Work Party
Fri Apr 12, 10-12, Fig Pruning

We got a surprise in October when we pulled out the cucumbers and peppers that were planted near an olla. Carefully, we used the hori hori and excavated around the base of the olla to see which plants took advantage of the water. A small fig tree, planted about 10 feet from the olla, had wrapped its roots tightly around the brown water vessel. And Nancy wondered why her little fig didn’t need any water during the dry months!

Now we know that root pruning is another task for the winter to-do list. Check your own garden bed sites to see if any plants may be robbing water from your edibles.

Here is a good chart on root depth per plant (page 1). Following that is an interesting chart on the water needed to provide certain nutrition parameters by crop.

 

 

 

 

 

 

 

Last week, three of us heard our State Climatologist Nick Bond speak. Nick is still delivering the same message; in general, western Washington is in for dryer summers and wetter winters. In addition to being water efficient, the more water we can collect during the winter the more we will have in the summer.

We are lucky to have our cisterns and, if we had one more, we could make it through the summer. Last year we used our 4,000 gallons from our cisterns plus 1,300 from the City water supply.

We will continue to explore ways to increase water efficiency. Check out the recent addition to the Perforated Pipe Page.

Ruth