Tomatoes and Hairy Vetch

[Todd]

The is an article in the September issue of California Farmer, pp50-51, about some ARS research using hairy vetch and tomatoes. I'll try to summerize it since it's not on the web:

"...based on a five year sustainable agriculture study...the scientists showed that at least 10 genes in the leaves of tomatoes grown in the sustainable system were turned on longer or, 'over-expressed, allowing those tomatoes to live longer than tomatoes grown on the plastic mulch...were more resistant to common foliar plant diseases (bacterial spot, early blight, Seporia leaf spot)...disease symptoms became apparent 65 days after transplanting on the plastic ...did not appear until 84 days (with the hairy vetch)...and never became as severe...they also produced 2-3 weeks longer...the researchers say they believe the cover crop allows the tomatoe root system to produce more cytokins..." They also used half the fertilizer rate (compared to the plastic mulch tomatoes).

The article didn't say what the "sustainable system" was. However, it sounds like it was sort of no-till, that is, a cover crop of hairy vetch was planted in fall and then the tomatoes transplanted into the dead hairy vetch in spring.

Given the fact that hairy vetch can get extremely long, 5 feet or more, I don't know whether they did anything to chop it up prior to planting or if this was not necessary since there wasn't something like bell beans for it to climb on.

Todd

 

[Gingergirl]

That's pretty impressive.

I have read that in Zone 4, if you want the Hairy Vetch to be dead for early spring planting, it needs to be seeded in July-August. For a later planting, seeded in Sept-Oct. However, it can lay dormant and begin growth again as late as April. Also read that shearing it as it begins first bloom will kill it.
The seeds ripen quickly and almost immediately shatter. The root system can be up to 3 feet deep and given support (such as oats or rye) will climb 3-4 feet.
(IIRC this was in a Massachutes agr. article)

In another article (Purdue I think) it was found that several "bad" nematodes were encouraged into the soil by the vetch...but I wasn't clear if this was in reference only to the upper Great Lakes.

I do have one bed that I may give this a test on, planting the vetch and then putting in tomates in that bed and the one next to it next summer. Nitrogen is cheap, but the diseases are expensive.

 

[Todd]

The article also had this sidebar:

"Why hairy vetch? A choice of cover crop species should take into account winter-hardiness, efficiency in fixing nitrogen and phosphorous and the length of the growing season. Hairy vetch rated the highest in fixing nitrogen and producing biomass and the length of the growing season. Hairy vetch rated highest in vigor, winter-hardiness and nitrogen content. Bigflower vetch also rated very high, but bigflower vetch seed is difficult to obtain.

"The next highest-rated winter annual legume was crimson clover followed by common vetch. Crimson clover provides excellent biomass for mulching and attracts insects but does not have as high a nitrogen content (2.5%) as hairy vetch (4.0%)."

It seems to me that a home gardener who was willing to give up the fixed nitrogen and use a litle more fertilizer would get some of the benefits by simply mulching with a legume like alfalfa hay.

I've used alfalfa hay as mulch for all our vegie crops for years and it does appear that we have few disease problems. Since I haven't done comparative tomato tests at our place on plastic mulch, bare soil and alfalfa mulch, I don't know if my statement above is true. I do know that we simply don't have disease problems.

In addition, we are just pulling our tomatoes today and they have been in since the middle of May and are still producing. We're pulling them now because it's getting pretty cold - it went down to 38 degrees last night and if it stays like this nothing more is going to ripen. I could protect them with plastic to warm them up but I need to get the garden totally put to bed for the year.

Todd