Vegetable Garden, Round 2… the Fall Garden

Spots, rots and blights be damned… keep planting! That’s my advice to vegetable gardeners. We are about to enter Round Two of the gardening season and it can be very rewarding. I’m talking about the Fall garden. Sure, it’s still summer but by taking a few simple steps now you can be way head come September and October.

Rip out those blighted tomatoes, monster squash plants, ragged cukes and weedy patches. Then seed ‘em. I’m talking about beets, carrots, turnips (yes, turnips are tasty) lettuce and cilantro. Fall spinach is wonderful and September plantings will overwinter and provide spring crops. Transplant cool weather, cole crops (cabbage family).

The entire cabbage family thrives in the fall garden. Right now you can find six-packs of broccoli, cauliflower, Brussels sprouts (yes, Brussels sprouts are tasty) and cabbage in some garden centers. Get these transplants into the ground in mid-August and you’ll be enjoying nice harvests in late September and October. Many years the quality of the fall crops is better than spring.

Because fall air temperatures and day length are moderate and declining, the fall garden is very different that the spring version. Crop growth slows and quality holds very well. Weed growth slows and even stops in some cases, with the first frost. It’s a pleasure to work outside again without working up a sweat.


What to do with all of those dead and diseased plants? How about the wheelbarrow loads of weeds? Compost them! That’s right, compost them. Almost every composting book and manual warns against this. Nonsense! (most of the time). The vast majority of the diseases that affect our vegetable crops will not be spread, enhanced or aggravated by composting the affected foliage. Several reasons. First, the compost pile is a very vicious place. Good fungi destroy the bad. Even simple soil incorporation of dead plants works in your favor. There are a few exceptions but don’t sweat it. Compost that stuff.

Consider the farmers. Do they put diseased plants in the trash? Nope. They plow them down and rotate crop location. Sure, our rotation options in a small garden are limited. Makes composting diseased stuff a smart move. Finally, understand that our most common fungal, bacterial and viral pathogens survive in or near the garden naturally. Even if you tried extreme sanitation, you’ll be visited by the ancestors of 2009 powdery mildew, early blight and botrytis in 2010.

What about those weeds. Two potential problems… weed seeds and the fleshy storage organs of perennials. Yea, it would be nice to eliminate weed seeds but I’d be willing to bet that a lot of those weeds in your garden have already set and dropped a lot of seed. When you pull them up even more will shed. Are you going to pick them up? Didn’t think so. So what’s the dif if they go into the compost pile where they have less chance of survival? The perennials? I don’t know what planet those folks are from that talk about perennials surviving composting. Even a cold compost pile that is turned a few times will destroy perennial roots, rhizomes and stolons. So compost away! I think the warning about not composting weeds comes from the common experience of importing compost or manure from remote locations and discovering new weed species the next year. Yep, this bound to happen…. weed seeds. Some are annuals, some perennials. But the weeds we are pulling in our gardens this year have already taken up residence. Recycling them thru your compost does not make the situation worse. Compost ‘em!

Thousands of Flower Cultivars on Display at Penn State's Trials near Lancaster

Sometimes you just need a break from the gloom and doom of mid-summer plant disease epidemics (late blight) and want to look at pretty flowers. So that’s what I did this week and visited Penn State’s Southeast Pennsylvania Research and Extension Center, near Lancaster.

Each year, more than 1000 different cultivars of flowering annual plants are established and evaluated by Sr. Extension Educator, Alan Michael. Quite an undertaking. The results are of great interest to plant breeders, salesfolks, garden center managers, greenhouse operators, and plant lovers in general. As I write this, hundreds of folks are attending the open house which is held each July. I snuck out a day early to avoid the crowds. My pal Al gave me a personal tour of the trial highlights. One of the great things about the research center is that you, too, can drop in for a visit any weekday between 8 a.m and 3 p.m. The plants are well labeled and you are welcome to do a self-guided tour. I highly recommend it. Or do a virtual tour by visiting this website.

I am more of a fruit and vegetable guy than a posy lover but man does not live by bread alone so I also try to learn something about the ornamental plants. The Coleus and Petunia cultivars are knockouts. It is worth the trip just to see ‘Pretty Much Picasso’ Petunia. Begonias for full sunlight are stunning. Do you know Angelonia? Torenia? How about Calitunia (a Petunia x Calibrachoa cross). A handy cultivar list provided at the trials makes note taking easy.

So before the summer is over, take a day trip to the Flower Trials at Penn State’s research farm. Stop in Lancaster for a whoopee pie. If you’re free this Saturday, July 25, check out the “Summer Garden Experience”. It includes free lectures, Master Gardener demonstrations, a native plant sale and, of course, the flower trials.

Late Blight of Tomato Continues to Spread

You’ve been warned. Late blight is here and continues to affect commercial and home plantings of tomato and potato. A farmer friend called me minutes ago to report a farm right across the river where tomato was confirmed with late blight.

Now it seems a matter of time before we see wholesale injury to this popular crop. Although relatively dry weather has prevailed recently, morning dew in enough to support late blight infection.

I could say more but my co-horts in Lehigh Co have done a great job. See this link.

The best pictures I've seen are from Cornell.

Late blight of tomato and potato arrives early this year

I had hoped that I would not write about late blight this year. Usually it is August or September before late blight rears its head in our area. So writing about it in early July is a bad sign for gardeners and farmers. But it is here. A perverse combination of the widespread sale of infected tomato plants and abnormally cool, wet, weather in June was the perfect storm. The disease has been confirmed in almost all Northeastern and mid-Atlantic states, including in Lancaster and Lehigh counties in southeastern Pennsylvania.

This devastating fungal disease is a threat to all tomato and potato growers. It is the same fungus that was involved in the Irish potato famine of the 1840’s. While no one will starve in 2009 due to late blight, it appears that we are in for an unusually early and wide spread epidemic. Plant pathologists are reporting that this is the earliest the organism has been found in such a wide spread area of the Northeast U.S. The problem is, this fungus can travel many miles in the air, settling out on host plants and spreading infections. Apparently, widespread sale of infected transplants has inoculated the northeast. Many of these locations will be home gardens where it will go unnoticed until it is too late. Nearby commercial plantings are at risk.

The fungal pathogen involved in late blight disease is Phytophthora infestans. It thrives under cool (60-70 degree) moist (dew rain, humidity) conditions. Host plants include tomato, potato, other tomato family plants and, believe it or not, petunia. Foliage, stems and fruit blackens. Unlike the slow progression of early blight described in the previous blog, late blight moves like lightning. That’s why plant pathologists watch like hawks for its emergence and alert commercial growers to its presence.

Fungicides can protect plants and limit the spread of the disease. Famers have good options but must be vigilant and proactive. Gardeners have the fungicides chlorothalonil and copper. Copper is a poor second choice but some forms are organically approved. More details, instructions and pictures from Cornell University can be found here. And at this Penn State site. Plant pathologists recommend treating now, rather than waiting for signs of infection. This fungus is amongus.

Spots and Rots and Blights...Oh My! Plant Diseases 101

You might find lions and tigers and bears frightening but farmers and gardeners would disagree. Groundhogs and rabbits and deer can be more destructive. And then there are the fungi. Early blight, late blight and anthracnose. Black spot and mildew and scab. Rusts and rots and wilts. It’s a jungle out there!

Fungi are certainly the most common organisms associated with plant disease. I say “associated” because the pathogen, by itself, does not equal disease. A susceptible host plant and the proper environment are also necessary.

Here’s a timely example. By now, tomato growers are probably noticing brown spots and perhaps yellowing of the lower leaves. On closer inspection, you may see that the “spot” is actually a lesion that has concentric rings of dead tissue. There may be tiny black dots in the dead tissue. As the season progresses more and more foliage is killed. Fruit infections cause soft spots and rots. All of these symptoms describe the common tomato disease called early blight. The disease also affects potato and eggplant. Some of you will be happy to learn that two weeds, horse nettle and black nightshade, are vulnerable, too. Since all of these plants are related, it is not surprising that they are susceptible hosts for the same pathogen. Note also that the early blight pathogen has no effect on asparagus, beans, cucumbers or you. (Sometimes folks ask if it is OK to eat diseased vegetables. It is.). The pathogen has a scientific name Alternaria solani.

OK we have a susceptible plant and a pathogen. The final ingredient needed for disease is the proper environment. This pathogen thrives and reproduces well under warm, moist conditions. The weather in the month of June, 2009 in Southeastern, PA was about perfect for early blight. Especially for tomatoes that were left to sprawl on the ground rather than trained to a support system which favored air movement and leaf drying.

Bingo! Early Blight of Tomato!

Maybe that was more than you wanted to know about early blight but it is useful. You can manage this disease (and all others) by thinking about three key disease ingredients: pathogen, host and environment. Sometimes it is possible and effective to eliminate the pathogen. But it can be equally effective to grow non-susceptible host plants or modify the environment. Disease resistant varieties have been developed for many of your favorite plants. Look for them when buying seed. Learn about the conditions that favor disease. Do what you can to change it. For most fungal diseases that means increasing air movement and reducing leaf wetness.

For a descriptions and gory pictures of common vegetable diseases, type “vegetable disease” into the search box at www.agsci.psu.edu.

For a complete guide to growing tomatoes and info on more tomato diseases go to http://pubs.cas.psu.edu/FreePubs/pdfs/uj230.pdf

Thanks to University of Minnesota Extension for the nice image of early blight shown above.

April Showers Bring May Flowers but… June Monsoons are not a Boon for Most Plants

Just checked a weather web site and it confirms the feeling most of us in Southeastern PA have…soggy. Only three days out of the last eighteen did not have measurable precipitation. Six inches in the last 30 days; this is 160 % of normal. Minimal sunshine. Below normal temperatures.

My farm friends are hurting. Can’t plant. Too wet. You might not be thinking of Halloween yet but farmers are because pumpkins are a 100-day crop that needs to be in the ground now in order to make fruit by this fall. The sweet corn you enjoy in August is planted in June. Perishable crops such as strawberries that are at peak maturity are melting in the field. Weeds thrive in these conditions and it is impossible to cultivate wet soil. Saturated soils and continually wet foliage are ideal for many plant diseases. Ever seen plant wilt because it’s too wet? I have.

Mother Nature can be cruel to folks trying to grow stuff …. gardeners and farmers. As hard as this can be on gardeners, consider the farmer whose income is dependent on favorable weather. Most fruit and vegetable farmers will take a dry year over a wet one, especially if they have access to irrigation.

Any upside to all of this? Well your lawn probably looks great. If you planted trees this spring the watering chore has been minimal. And this can’t last forever. Gardeners and farmers have to be optimists because if it ain’t one thing it’s another when you are playing ball with Mother Nature.

For those growing ornamental plants, Penn State has a very helpful web site describing plant diseases and their management. Check it out.

Poison Ivy

As I drove into our office complex today I noticed a member of the grounds crew cleaning up stems that had been sheared from a privet hedge. Most of it was privet, but I also knew that there was plenty of poison ivy in there, too. I had been observing it for a few weeks, thinking about the challenge of killing poison ivy that is entwined in landscape plants.

I stopped and chatted with him to be sure that he knew what he was dealing with. Sure enough, his arms were blistered up from previous encounters with this weed. We shared remedies for the itch, methods to control the weed and ended up wondering if there was anything positive about poison ivy. I know that bees and other insects collect its nectar and pollen; birds eat the seed. The grounds man thought there might be some therapeutic, whole-body effect from having the rash… what a great attitude!

Poison ivy, Toxicodendron radicans, is a native, perennial, woody vine that is the major cause of allergic dermatitis in the Eastern U.S. according to Weeds of the Northeast, (Cornell University Press). It is very commonly found in Pennsylvania and easy to identify, despite the fact that its leaf characteristics vary somewhat, depending on where it is growing. “Leaflets of three, let it be”, is a saying that begins to draw your attention to key characteristics. The center leaflet extends on a relatively long stalk. The upper surfaces of the leaves are often quite shiny, especially when growing in full sunlight. The leaflets are usually lobed or coarsely toothed. Mature plants climb trees with the aid of aerial rootlets and the older stems become rope-like and quite hairy. But poison ivy is often found running along the ground in the forest understory, and there, the leaves are dull green. Both the newly emerging spring growth and fall foliage are red. Contact with any part of the plant causes a skin rash in most people.

Since poison ivy is perennial, it is not easily controlled by mechanical methods such as mulching, pulling or mowing. In woods and other unmanaged areas, just learn to recognize it and enjoy its beauty in all seasons. If it is growing in places where you or others (unsuspecting kids) are likely to bump into it, you can control it chemically.

Two herbicides, glyphosate (sold a Roundup and many other trade names) and triclopyr (Sold as Brush-B-Gone and others) will kill poison ivy. I think triclopyr is most effective. Glyphosate products will kill or injure any green plant that it contacts. Triclopyr will not injure grasses and this may make it useful in some settings. Both products are applied to the foliage of target weeds. In fact, healthy weed foliage is important for maximum uptake and translocation of the herbicide. Neither product is root absorbed so you can be quite selective by applying the herbicide only where you want it. As long as desirable plant foliage is not contacted it is safe from injury. Read the labels for complete instructions.

So, before the year is over, and once the poison ivy re-grows from the hedge (which it surely will) I hope to help the grounds crew selectively and carefully wipe one of these herbicides onto the poison ivy growing in the privet, avoiding all privet foliage.