Tomato Time

Ask most vegetable gardeners what single thing they would not live without in their garden and it is probably the tomato. Makes sense, tomatoes are easy to grow and reliably produce lots of fruit; they are tasty, good for you and bear from July till frost. There is a huge selection of varieties to choose from so tomato growers don’t get bored. And it is just plain satisfying to pick a big, fat, ripe tomato and fix yourself that first sandwich or salad.

Growing tomatoes is so easy I hesitate to offer advice but here goes. Even veteran tomato growers got a surprise last year with late blight and I’ll offer a few thought s on this disease. Here’s a link to Penn State’s tomato growing guide. See page 55.  It contains lots of good detail on tomato culture…and its relative, the eggplant.

Grow your own transplants or rely on the local greenhouse? That is a big question. Certainly growing your own plants gives you more control over what varieties you’ll enjoy. But many of us just don’t have the time, growing conditions or skill to produce a good transplant. I find that small, local greenhouses offer the best chance at getting an excellent quality plant as well as decent variety selection. Try your local farm market, too. Sometimes farmers start more transplants than they need and sell the rest.

Tomatoes are heat loving plants. They will not tolerate a frost so we wait until mid-May in Bucks County to plant them out, unless you have some device that will protect them or are willing to gamble that Mother Nature is looking out for you. By Mother’s Day, we are almost always past danger of a hard freeze, so that’s a good tomato planting guideline. Makes sense to look at that 10 day outlook and adjust as necessary. You can plant out earlier using low tunnels, wall-of-water, row covers and other heat retention devices if you are the kind of person who wants that first tomato on the block.

Varieties… the list is endless. Entire websites are devoted to tomato seeds and varieties. Here are a few suggestions based on Penn State evaluations, personal experience and high praise from knowledgeable tomato people.
Brandyboy… an improved Brandywine type will give you excellent size and flavor without the downsides of straight Brandywine that heirloom folks praise. Fabulous…is just that, a fabulous, tasty slicer that will not disappoint you. Celebrity is an early fruiting, smaller but reliably good slicer. Mortgage Lifter is a good choice if you are in the heirloom market; and how can we overlook a variety called Bucks County from Burpee.

Plant breeders have been taking the best qualities of heirloom types and combining them with traits that improve yield uniformity and disease resistance. I’m not talking about those hard, red cardboard tasting things you find in the mega-mart. Plant a Brandywine and a Brandyboy side by side and judge for yourself. Space is limited so I’ll leave it to you to explore the plum, cherry, grape Roma and other small types but I will drop a name…Mountain Magic is reported to be a superb new “salad” size tomato that will be available in limited quality this year. In addition to yield and flavor it is resistant to late blight.

Ah late blight… the tomato/potato disease that took a lot of the fun out of last year’s garden. You may recall tomatoes turning a greasy, black color and croaking about mid July. For a more detailed discussion of the disease, check out previous blog entries.

Bottom line… no reason to expect late blight to be the scourge it was in 2009 but keep your eyes open and let us know if you see it. Gardening-wise, there are no special gardening practices that you can employ to prevent late blight. No need to sterilize soil, tools tec. Rotating planting location is always a good practice but will have no effect on late blight.

More likely, our old nemesis, early blight and Septoria leaf blight, will be infecting plants. Neither are the devastating fruit rotter and plant killer that late blight is but they overwinter her very well. Stake or cage plants to encourage quick drying and you’ll see less of these diseases. Inspect plants when you purchase and bypass those with spotted or yellowing leaves.

A final thought… consider planting through black plastic mulch. It is amazing what it does for soil heat and water retention, weed control and overall soil physical prosperities.

Late Blight - 2010

Ok. First, the take home message…. Tomatoes growers should not expect the 2009 epidemic of Late Blight to return in 2010. And… the disease organism that causes late blight has not survived in soil, pots, stakes or other non-living tissue in Pennsylvania. So, chill out on all of those elaborate plans to sanitize the garden. If Late Blight interests you, read on. If you grew potatoes last year, and have any left over, be sure to read to the end of this blog because you could cause a problem.

Last week I spent an entire day, in one room….learning about tomato production at the Mid-Atlantic Fruit and Vegetable Growers Conference in Hershey, PA. I was in charge of making sure the projector worked and the lighting was conducive to learning, otherwise I would have slipped out to catch that session on horseradish, among others, down the hall.

A lot of time in the tomato marathon was devoted to late blight, the disease that caused widespread destruction of tomatoes in the Northeast US last summer. Two things were responsible for that epidemic. One… infected transplants were sold throughout the Northeast thru the “Big Box" stores. The stores were supplied by a large greenhouse business that had late blight (a disease caused by a fungus-like organism) in their production system. I am sure that neither the stores nor the greenhouse business intended to create such an epidemic. But the end result was distribution of infected plants over the Northeast... a devilishly effective Step One: spread a very contagious organism over a wide geographic area. Late Blight spreads by spores which can blow 30-40 miles in moist air. It can infect tomato and potato as well as some weeds in the tomato family (and petunia, I learned).

Thanks to an eagle-eyed plant pathologist from Cornell, the problem was diagnosed every early. He blew a whistle and everyone paid attention, otherwise, it could have been worse. He said it may have been the most constructive thing he has done in his long career.

Step Two was Mother Nature. She picked 2009 to provide excess moisture and cooler than normal temperatures from June until September. Perfect for the Late Blight organism. Hey, whose side are you on Ma, the tomatoes or some pathogen? I guess we know now. Seems she loves all of Her creations, including Late Blight. Hmmm.

The good news is that the organism that causes Late Blight has no history of overwintering in the Northeast U.S. Once infected plants die, so does the disease. Plant pathologists are concerned about a situation in which late blight does develop the capacity to overwinter here, but so far that has not occurred (as far as they know).

So again, the really good news is that both gardeners and farmers have no reason to expect late blight to be any more of a threat in 2010 than it was in any other year. And 2009 can be considered an unusual year for the disease. Since the organism requiures a living host, there is no need to plan elaborate crop rotations or go to extremes in trying to kill what is already dead. Dead tomatoes equal dead late blight. Unless the spuds get us….

Now about those potatoes…. Recall that late blight can survive in living tissue and since the same organism infects both tomatoes and potatoes … do you know where your spuds are? The concern is that infected potatoes are laying cull piles or worse, stockpiled for planting. Don’t do this! Buy certified, clean, potato planting stock!. It ain’t worth starting the epidemic of 2010 to save a few bucks on seed potatoes. And that means your precious heirloom varieties, too. If you grew potatoes in 2009 and experienced late blight, be alert for volunteer spuds next spring and destroy them.

No problem with saved tomato seed.

I located an excellent summary of late blight and its management at UMass extension. It provides and excellent overview and advice for gardeners, including those using the organic approach.

For a utube segment by PSU's own plant pathologist, Beth Gugino, see this.

Tomato Troubles

Most gardeners are starting to harvest tomatoes by now. Some have been at it for a month. So, here at the Penn State Extension office, calls about tomato trouble are starting to come in. Want to see gory pictures of tomato problems? Check out Penn State and our sister institution Texas A& M for some exquisite shots.

This week I saw the following:
Early blight, the most common fungal disease of tomato. It causes lower leaves to turn yellow then brown. On closer examination you’ll see brown spots with concentric rings of dead tissue. Later, tomato fruit will develop rotten spots. Staking plants to improve air circulation and quick drying is an important control measure. Fungicides work very well but most gardeners are not interested in spraying plants and despite the infection, plants usually produce a decent crop… for a few weeks. The fungicide chlorothalonil is effective in preventing the disease spread and is available over the counter in garden centers. Organic gardeners can use copper fungicides and get limited control.
My strategy: 1) Stake ‘em up early and often 2) have a second planting coming on and abandon the first when the disease overwhelms them in late August. Go ahead and compost that old stuff.

Blossom end rot causes a dry, leathery, brown rot on the blossom end (opposite the stem end) of fruit. Caused by calcium deficiency. Hard to fix now. Soil test and add needed calcium with lime or gypsum in the fall to boost Ca levels for next year. A Penn State Soil test will tell you how much. Sometimes blossom end rot shows up in gardens with adequate calcium. Anything that prevents the plant from absorbing calcium from the soil, such as moisture extremes or root damage can result in blossom end rot. Sometimes plants have affected fruit for a while and then snap out of it.

Viral diseases mimic herbicide injury. Saw several cases last week. My guess is cucumber mosaic virus but that is just an educated guess. Viral diseases cause weird plant distortion and mottled, mosaic patterns (several shades of color) on fol age and fruit. Fruit are often undersized and misshapen. Viral diseases are a tough case because there is no cure. The virus lives in other plants, often hundreds of species, including ornamentals and weeds and is transmitted by insects such as aphids and leaf hoppers. They can even be transmitted by human handling of infected plants. You may see viral symptoms on beans and vine crops also. I do not know why virus diseases are devastating one year and almost non-existent in another. This is looking like a good year for viral diseases.

By the way, none of these problems make the tomatoes inedible, just cut out the affected parts and chow down. And another thing….aren’t you glad that your paycheck isn’t dependant on your horticultural skills and Mother Nature. That’s the high risk game farmers are in.