Time will tell if our methods worked or not in our open garden. I'm southeast of Seattle, WA.

Our tomatoes got late blight 2010 & removed plants as well as fallen leaves, though know not all were removed as caught up in the mulch. I don't know if it survives in the roots, but didn't think so.

The area where I grow tomatoes has the most sunshine, which is in short supply in my forest clearing where we live, so I have just 3 areas I can grow tomatoes: large 25' long strip, 8'x8' between pear trees, & 4'x3' behind rhubarb. I chose to leave the area behind rhubarb unplanted & used the compost there are summer in various projects.

Fall 2010 - layered up at least a foot of various organic matter (partially composted horse manure, shredded leaves, used coffee grounds, shredded paper, etc.) over time & kept covered with burlap. The final addition was fresh horse manure with some wood pellets (sawdust) bedding.

early spring 2011 - applied new wood chips to paths surrounding garden beds, which also helped to "fill" in the area around the high mounds of the beds from our layering.

Spring 2011 - removed burlap & covered with black plastic to warm soil

mid-April -
*installed tomato supports
*transplanted tomatoes with a 8oz yogurt cup of mixture into the planting hole (dolomite lime, bonemeal, complete organic fertilizer)
*mulched with straw along with silver Starbucks coffee bags for reflected heat/light *watering only with soaker hoses

during the summer -
*removed any self sown tomato seedlings anywhere they show up
*transplanted potatoes that also showed up nearby from missed harvest of tubers last Sept.
*no disturbing of soil other than those 2 things

Now at end of Aug -
*Glacier tomato plant has the only nearly ripe tomato so far, other plants are loaded with fruit & blooms yet looking as healthy as ever
*drizzle for a few days this week will test how well we've protected plants from the splashing up of soil onto the leaves as that's how I understood it to spread.

Here is a link that might be useful: tips for dealing with blight

Most every one suggests not planting a member of the nightshade family in that soil for about 5 years. Some people have reported success solarizing the soil, while others have not had good results.
I find a soil well endowed with organic matter that is evenly moist but well drained and is well mulch seems to grow tomaotes year after year with no sign of those diseases.

corinne1 and kimmsr, thank you for responding. The info so far on this thread is valuable to me.

kimmsr, you wrote: "I find a soil well endowed with organic matter that is evenly moist but well drained and is well mulch seems to grow tomaotes year after year with no sign of those diseases."

I wish I could agree. I've been growing tomatoes and potatoes for 30 years on our place, using organic methods on a sand-based soil, building the organic matter in the soil each year. No problems with blight for 29 years. Then our potatoes and tomatoes got it, just this year. (Well, it's only been in the last two coolish years that I've heard reports of late blight in our valley.)

What is the level of organic matter in your soil? Mine has been fairly consistently in the 6 to 8 percent range for quite some time now and each year, right after planting tomatoes a good thick mulch goes down.

kimmsr, we used to grow our tomatoes outdoors. Hoping for a more prolific crop that would ripen before the autumn cold weather stopped the ripening, we put up a greenhouse in spring 2010. We had no blight that year (in either our greenhouse tomatoes or our potato patch outdoors).

In the greenhouse where we've planted most of our tomato plants for the last two years, the soil in our raised beds runs 18-23% organic matter - but is well-drained due to sand being the main mineral constituent.

Spores from both early and late blight can live on plant debris in soils and one of the ways the are spread to plants is water splashing the soil onto the plants which is why a good mulch helps, that keeps water from splashing soil. The other thing that helps is bacterial activity in the soil and greenhouse soils often do not have much, if any, bacterial activity, and that is why the greenhouses around me replace their soil every year. Since the spores of these plant diseases also travel on the wind that can be another though less likely source. Infected seeds and plants are the most common sources of the disease pathogens.

kimmsr, you wrote"Spores from both early and late blight can live on plant debris in soils and one of the ways the are spread to plants is water splashing the soil onto the plants which is why a good mulch helps, that keeps water from splashing soil. The other thing that helps is bacterial activity in the soil and greenhouse soils often do not have much, if any, bacterial activity, and that is why the greenhouses around me replace their soil every year. Since the spores of these plant diseases also travel on the wind that can be another though less likely source. Infected seeds and plants are the most common sources of the disease pathogens."

My potatoes got blight, and I was growing them in mulch.

I intend to increase the bacterial activity in my greenhouse beds (and outdoor beds, too) next year with manure tea. I just recently built a new manure-tea barrel & faucet arrangement.

About the possibility of infected seeds or seedlings: In my region, the organic gardeners, the full-on farmers, and the professional gov't agronomic disease experts all voice the opinion that the main way blight is spreading is spores carried on the breezes. The situation is so bad on the west coast of our province (where it is much damper, climatically) that virtually nobody farms potatoes organically - they're all treating the potato fields with fungicides. However, until the last couple years, blight was nearly unheard of in the province's interior, where I live.

Perhaps this from Ohio State University might be of some help.

Here is a link that might be useful: Early Blight of Tomatoes adn Potatoes

corinne1, your experience (and weather) sounded so similar to my own - except blight struck your plants a year before ours. So, of course, I'm very interested to find out how your coping methods and practices have worked out with the 2011 plantings & crop. Sounded good as of the point when you posted on this thread.

If you read this, would you please update on what you posted earlier, so I can know what happened for you late this summer?

And... Anyone else who has personal experience with replanting tomatoes on the same site (such as in a greenhouse or small garden) the year after a late-blight attack, please do share your experience. Thanks.

joel_bc-- Here's the update: No blight or sign of disease this year even after the drizzly rain & mist from the end of August as I wrote about before.

-No plastic hoop or covering on tomatoes. Removed some of the leaves from indeterminate types in cages to increase air flow, but fruits are still covered by foliage. I was concerned about the leaves staying too wet with morning dew & the pruning seems to have worked.

-Growing tomatoes on the dry side & only turning on soaker hoses when the droopy leaves don't recover in cool of evening. Usually, then turn on for 3 hours that evening or next morning. I'm guessing I've done this around 6 times, so far this summer including this past week Sept. 7.

-Allowed some of the potatoes that sprouted up to continue to grow. These are within 3' of some of the tomato plants.

-The moved potatoes were harvested last week. A small crop about 5# or so of mostly small new potatoes, but I didn't water them more than a few times. Slugs devoured quite a bit of them, so when plants were yellowed & brown I dug them.

Ripening report: Glacier has 3 almost ready. Waiting until 1st one is almost overripe as suggested by Ciscoe Morris during a garden talk a few years ago at Windmill Gardens in Sumner, WA. A few other cherry types have orange tomatoes. Most are still flowering & green.

On Labor Day weekend in recent years I've stopped the growth by pinching tips & removing the blooms & very small fruits to encourage the plant to put energy into ripening existing fruit. This year I chose to leave them be since our season is so late with the dry, summer heat here now in Sept.

I'm quite heartened by what you've posted on this thread, Corinne. I want to be more selective about which varieties I plant next year. Also, I've tried to do a really good clean-up of the greenhouse soil in which the tomatoes grew, and also of the potato patch soil.

You had many good suggestions, good practices. I'm heeding all of them.

The idea of using soaker hoses makes sense - but our rains and humid weather are uncontrollable factors here. Of course, my tomatoes were in a greenhouse, so rain (as such) did not fall on the leaves. We tried to water at the roots, not on the leaves.

Well, what can I say? I'd like to have a recovery like your tomato-garden had.

Just wanted to thank everyone who shared info on this topic of how to proceed in gardening when you've had blight in your solanaceous plants. As I mentioned, many people in my region have had very sad experiences with potatoes and tomatoes in 2010 and 2011. I share info with local people via a gardening blog I write, so I'm passing on what I've been learning from you folks here.

Anyone else reading this thread is encouraged to share their own experience with tomato gardening in the years succeeding a nasty blight episode. I do appreciate it.

Joel_bc: Did you run a fan 24/7 in the greenhouse?

End of Sept update:

Tomato plants still look green, flowering, & healthy with the exception of the Glacier, an earlier fruiting variety yellowing a bit after producing the most ripe tomatoes here.

Now picking ripe cherry types, Glacier, & Early Girls.

Our Indian summer weather has been better than our July weather! Temps have been in 80s for 10 days, then about a week of mid 60s, a few days of 70s & 80s, then now going to be showery, blustery & mid 60s for a few days, a few days of cloudy, then more rain at the end of the week.

The winds will challenge the supports heavy with fruit, so I'll be on the lookout for fallen plants. Another gardening friend had nearly all of her potted tomatoes on her deck topple the other night with the wind. The forest here protects from some of the wind as would a hoophouse/greenhouse.

On another forum, I got a response from a gardener who had who had dealt with bad blight one year. He said the next year he planted in raised beds, with extra spacing between plants, and used Safer's fungicide - and had no problems.

I know the Safer brand. I've used their insecticidal soap for aphids outdoors. I'm going to have a look at their fungicide. I'd want to feel good about what's in it before using it.

Fall rains are here & no blight in 2011 after blight in 2010! We're pulling up the plants this weekend & harvesting the rest of the fruit for inside ripening.

I am reading The Biological Farmer by Gary Zimmer, who is one of the top bio-ag experts in the country.

He says three things that contribute to blight (all types) is lack of calcium, lack of zinc, and lack of copper in the soil.

There are three basic types of calcium:

1. Calcium magnesium carbonate (CaMg(CO3)2, also called dolomite lime). If you have sandy soil that needs lime and magnesium, this is what you use.

2. Calcium carbonate (CaCO3, also called ag-lime, agricultural lime, or garden lime). It is used on clay soils that don't need any additional magnesium.

3. Calcium sulfate (CaSO4�2H2O, also called gypsum). It won't change the soil pH. Applying gypsum to an acid soil (pH less than 5.5) can have adverse effects on certain crops by displacing soil aluminum, which is toxic to plant roots. Use lime until your pH is at the desired level. Then use gypsum to add more calcium.

Don't use lime to raise your pH level, use lime to balance your soil calcium levels.

Sue

Sue,
Thanks for posting information about calcium. I've not used any gypsum & probably won't as soil still acidic.

Corrine