Perfect weather can make tomatoes suffer...

A favorite water cooler topic this summer is the odd weather we've been experiencing. Winter ended early & warm temperatures broke records in March. Most of us planted tomatoes early & were dreaming of a record-breaking harvest when we were hit by multiple hard frosts. This summer has been sunny & dry interrupted occassionoally by a pelting rain or thunderstorm that leaves heat & drought-stressed plants in water-logged soil.

As we enter peak tomato season, we are seeing more Blossom End Rot than normal. This is not a disease caused by a fungus or bacteria, but by environmental conditions that may or may not be under our control. Just as those first tomatoes turn red, the end farthest from the stem (where the shriveled blossom may still be present) turns black - dashing our hopes for a juicy tomato sandwich.

In my book, preventing Blossom End Rot comes down to something often overlooked - growing a healthy root system. Blossom End Rot only develops when plants experience the extremes of soil moisture (both too much & too little). Roots die back under both conditions & cannot recover to keep up with fast-growing plants. Technically, tomatoes are not taking up enough calcium for rapidly growing fruits, but unless your soil is seriously depleted, it's the fluctuating moisture levels & struggling roots that tip the scale in favor of this disease.

Usually, all that's needed is a reminder to mulch gardens & water plants during dry weather. I think more people are experiencing this problem in 2012 because of this year's early weather. Tomatoes are warm-season plants. While we were breaking out shorts & tank tops this spring and planting our gardens, the soil was probably still too cold to result in a good root system. If nitrogen fertilizer was applied to speed up growth, plants grew rapidly above-ground at the expense of the roots. Forecasts of rain didn't materialize so we watered after plants were already water-stressed. In some cases, the use of black plastic mulch (popular in our area) made monitoring soil moisture a guessing game.

The good news is that this is an early-season problem - meaning it generally affects the first fruit. You can still get good tomatoes if you mulch & address water issues. Just be sure to mulch with a material that allows water to slowly penetrate into your soil. This type of mulch makes what water you receive from nature available longer to your tomatoes - a thick layer of straw, newspaper, or wood chips will do the trick. If you've seen Blossom End Rot in your garden this year and are doing everything else right, be sure to check your soil pH and add lime this fall if test results call for it. (target pH = 6.5)

Blossom End Rot on Tomatoes



Unwelcome tent campers...

Something bright caught my eye as I drove through the woods, causing me to stop the car and check it out. It was about mid-way up the tree, just about eye level. As I approached, I could see a web of silk filled with small, dark caterpillars spanning the fork of a maple sapling branch. I recognized it as a tent caterpillar, an insect that is capable of totally defoliating a tree. There are two species in Pennsylvania; Eastern Tent Caterpillar Malacosoma americanum and Forest Tent Caterpillar Malacosoma disstria. Eastern Tent Caterpillar arrives in the spring, while Forest Tent Caterpillar returns in autumn.

It's important to make the distinction, because one is worth controlling while the other is not. Any time a deciduous tree is defoliated early in the growing season, it's more serious than if it occurs later. Just as squirrels store food before winter, trees store food in their roots during winter. This provides the energy needed to leaf out in the spring. Once leaves unfold, trees begin manufacturing their own food again (carbohydrates and sugars) through the process of photosynthesis. When autumn frosts arrive, trees send this food back into "root storage".

If a tree is defoliated by tent caterpillars as the foliage appears in spring, it's forced to leaf out a second time before its had a chance to make more food. This process depletes food reserves even further and leaves trees vulnerable if there is additional stress during the growing season. Think other insects, hail damage, frosts, diseases - any number of things can happen.

If caught early, and the tent is within reach, you can either squish the insects in their tent or prune the tent out. If the tent occurs where structural branches connect, is out of reach, or you are squeamish about the squish factor, consider spraying with Hot Pepper Wax. There's no need to wait for the insects to emerge from the protection of their tent at night to spray. Simply saturate the tent with Hot Pepper Wax Insect Repellent any time during the day and these caterpillars will be "fumigated" within their tent.

With rare exception, there's no need to spray the Forest Tent Caterpillar that appears in the fall. Since they damage trees just before they'd naturally drop their leaves, the trees have already made enough food for winter and won't be seriously hurt. No major harm means no control needed and more time to enjoy your garden.

Eastern Tent Caterpillars - May 2012

Maples pay a price for spring color...

This has been a spring to remember if you live in the northeastern United States. March broke high temperature records causing spring flowering bulbs and trees to bloom almost a month early. April was drier than normal and alternated between warm days and freezing nights. then as our native trees greened up, they morphed into a rainbow of color! In addition to the normal soft greens of spring, a cheery red appeared against blue skies.

While we expect an array of color in autumn, bright red maples in spring demanded a closer look. Anticipating I'd find tiny red flowers (though a bit confused because I know maples normally flower with the daffodils in our area), I was surprised to see that the red coloring was due to a heavy crop of samaras or seeds - aka "helicopters". Closer inspection of the maple in my front yard revealed the same thing, only in green.

I spent a couple of weeks blissfully enjoying the view until I was reminded that there will be consequences. I remembered fielding calls about "sick maple trees" in mid-summer years ago. People were concerned because their trees were thin on top and appeared to be dying. The trees had produced so many seeds in the spring that they didn't have enough energy left to produce a full leaf canopy. This was not an insect or disease issue (and trees weren't dying), but rather the result of perfect weather for maple seed production.

So is there anything we can or should do? Not right now - except to hope we don't get a secondary stress this summer. If the weather turns dry this summer and you can provide water to a specimen tree, do it. Most importantly, fight the urge to fertilize until the fall. Doing so now or during the summer will actually make things worse, though a little fertilizer this fall will give your tree a head start for next year.

Meanwhile, I'm going to enjoy the flight of the samaras that I know is coming while I add an extra cleaning of my rain gutters to my summer "to do" list.

Spring color as trees leaf out - April 2012

Red Samaras

Green Samaras



If April showers bring May flowers, what do "mild winters" bring?

In a week where the first flock of robbins & red-winged blackbirds arrived almost a month early, we are all enjoying what appears to be an early spring. We are talking about the winter that never arrived, and the majority of us in western PA are certainly not complaining. Lately, however, I'm hearing concerns about the impact of a warm winter - about what to expect this summer in the way of insect pests in our gardens.

Conventional wisdom is that a warm winter allows more insects to survive, resulting in increased insect damage in our gardens. While this may be true for some insects that spend their winter vacations buried deep in the ground, it may not be the case for many of the insects that feed on our veggies, flowers & trees. A lot will depend on where you (and those pests) live.

In our area, we've been having 50 degree days followed by nights that dip down into the twenties. For insects that spend the winter hiding under bark scales, leaf litter or other places that will be warmed enough to tempt those insects out into the open, it's unlikely they will be moving fast enough when temps drop to get back to their protective hideaways. That means that eggs may hatch out into more tender larval stages that will freeze before they can do any damage to plants. For those species, their numbers may actually decrease this year, resulting in fewer problems needing our attention later this summer.

Bottom line: No need to panic just yet about swarms of summer bugs. In fact, as I write this, I see a spring groundhog sorting through the sunflower shells beneath my bird feeders and am reminded that he will likely be more of a challenge to my garden this year than any insects.

We all have our own climate, soil and pest problems unique to where we live and what we choose to grow. Let's face it: gardening has so many inherent challenges that one more - even if it turns out to be a larger number of insects attacking my tomatoes - isn't going to tip the scales that much. Personally, I can't wait to see what this garden season brings. Like all who love gardening, I remain hopeful that this year's food and bloom harvest will be better than ever.

photo by Kathy Garrett

Help!...my begonia is dying!!

This was the frantic call I recently received from a family member. This was a new begonia that was so favored it had been brought indoors for the winter. My first thought was that it was just adapting to lower light levels, something that commonly happens when tender plants are moved inside. Unfortunately, the symptoms didn't match up to this theory. Instead of individual leaves slowly yellowing and falling off, the entire plant was going. After running through the usual suspects (spider mites and overwatering), I asked for a picture (see below). Problem solved...this begonia was not dying, but just entering dormancy.

How did I know? In addition to the stem and leaf shape, the photo included the plant tag - setting up a 'home run'. This told me it was a tuberous begonia Begonia tuberhybrida. Tuberous plants form tubers - think potatoes. It makes sense, really, that the presence of a tuber would allow any plant to go dormant and later use the sugars and starches stored in the tuber to re-grow.

Since this begonia is in a pot, it just needs to be kept in a cool dry place in the house - not in a dark closet or anywhere that you'll totally forget about it. While it doesn't need water during the winter, you want it to be where you'll notice when the new buds form on top of the tuber. This will be your signal to start watering again. If your potting soil has seen better days or you want a bigger root system (for a bigger plant), feel free to dig the tuber up (around February) and repot it (at the same depth that it was) with some fresh potting mix. Keep the soil moist but avoid watering directly on top of the tuber as you don't want it to rot.

Once your begonia begins growing again, use a dilute (half the label rate) solution of balanced fertilizer every couple of weeks for best results. (I have to admit, I've not fertilized anywhere near that often and always have beautiful plants - just avoid over-fertilizing at any one time - not an issue at my place.) Once you've passed the frost-free date in your area, move your begonias to a shady location outside and prepare for the blooms. Peak seasons are spring and fall, so don't worry if your plants bloom less in the heat of summer.

Tuberous begonia entering dormancy.

Tuberous begonia in bloom.

Remember your trees this fall!

Like you, I've been busy getting my yard (in this case a 100 acre farm & woodlot) ready for winter. This means a long list of outdoor tasks, not all of which will get done before winter's deadline. Rather than re-create my garden "to do" list in this space, I decided to focus on a couple of things you can do that will really make a big difference in the long-term success of your home landscape.

When you stop to think about it, trees & shrubs are the foundation or backdrop for everything else that we grow. They remain and slowly change over time by getting larger, creating shady habitats for other plants that will come & go over the years. On the other hand, forces beyond our control can make trees and shrubs change dramatically. Weakened branches can snap off in a storm...climate stress can pave the way for disease & insect problems...and all these problems can persist and get worse over time.

This year in our area (Northwestern Pennsylvania - zone 5) we saw it all - extremes of spring floods, a month-long drought in July, and record breaking rainfall in the months of September & October. All these events are stressful at the time, but easily forgotten a year or two down the road. Then a tree starts dying from the ground up, or a branch will go here or there...all a result of conditions we cannot control.

All is not lost. What we can do for those trees & shrubs that we hope survive well past our turn as "gardener in chief" are a couple of simple things that amount to "food & drink". The time of the year after leaves have dropped & before the ground freezes is short but is your chance to make a huge difference in the quality of your landscape long-term.

Woody ornamentals (i.e. trees & shrubs) will benefit greatly from a light application of a tree/shrub fertilizer (or even straight Nitrogen if that's all you have). Just spread a granular (or liquid spray) fertilizer evenly under the tree & out past the canopy if you can. Then let the snow or rain water it in. What I love about this time of year is that even the least expensive fast-release fertilizer won't burn.

You may be thinking "Fertilize in the Fall?? You're crazy!" - I know I did. I'd been taught that this would send a tree into winter in a weaker state making it more susceptible to the impending cold. Research done some time ago shows that tree/shrub roots (which are still actively growing in ground that is actually warmer than the air this time of year) will take up nutrients in the fall & store them until spring. Trees that are already hardened off will not break dormancy. As our "woodies" begin to grow & leaf out in the spring, these nutrients are gradually available. This avoids the problem of rapid/succulent growth that spring fertilizer applications can create.

Additionally, if you live where the ground freezes in winter, have a sandy soil that dries out quickly, or don't get plenty of rain just before winter, all "woodies" will benefit from a good drink of water. Just set a garden hose on low & let the water really soak in while you're planting tulips, a new tree just bought on sale, or digging dahlias for storage. Yes, you do need to move the hose occasionally, but anything you do now will pay dividends next year. Conversely, if the forecast is for plenty of rain, know that Mother Nature is taking care of it for you this year.

Once the ground is frozen, it's time to mulch. Normally, that's around Thanksgiving in our area. This means we still have a couple of weeks to give a healthy boost to those plants we want to nurture for years to come.

Topiary tomatoes - an unintended consequence

As I removed the last remaining tomato plant from my garden, I had time to ponder the question "Will I ever do this again?" After a second heart-breaking season in just three years, I'm seriously considering taking a break from growing tomatoes. Why such a rotten attitude? Two words: "late blight" - the same fungus that caused the Irish potato famine.

Normally, I enjoy the challenges of growing my own food. My tomatoes survived an early pruning by the ground hog that lives under my deck and significant defoliation by tobacco worms this year. I've come to expect the slow progression of early blight each season. The problem with late blight (as the name implies) is it doesn't appear until your tomatoes are doing so well you start to wonder if the supports will handle the weight of a multitude of green tomatoes. You begin to think you're home free, but the next thing you know, you're ripping out plants and tossing out tomatoes that will never ripen.

I know I'm not alone this year - the number one call at the local Master Gardener hotline in August was "What do I do about the blight?" Since one can be managed (early blight) and the other (late blight) is a swift death sentence, it's important to know which one you have. Luckily, the first symptoms appear in different places and are easy to distiinguish.

Early blight shows up as tiny brown spots on the lower leaves and progresses slowly up the plant. Eventually, the spots will get larger and the stems and fruit will be affected, but if you remove infected leaves as they appear, it's still possible to harvest a crop of vine-ripened tomatoes. If you are curious, take a close look at the larger leaf spots and you will see a pattern of concentric rings within each spot. (Think bulls-eye or ripples in a pond...)

Early Blight - early on

Late blight first appears as a "water-soaked" blotch on leaves (anywhere on the plant) and progresses rapidly to large dark brown spots on leaves and stems. A "water mark" is harder to see, but it's a symptom you'll never miss once you've seen it. If conditions are favorable, the blotches grow and tissue dies - eventually fruit starts to rot. Just a few days after the first symptoms, the plant is so affected that you will realize there's no salvaging this crop.

Late Blight - early water marks



Late Blight - more severe



Late Blight - worse



Both diseases can be prevented with an appropriate fungicide labeled for use on food crops. The critical point is that this treatment is "preventative" not "curative". It must be in place and covering all plant surfaces before fungal spores land. If not, infection will occur as soon as the weather cooperates. (Early blight likes it hot, wet and humid while late blight thrives during cooler, wet summer weather.)

As for "topiary tomatoes, that's the name I gave the one Roma tomato I planted this year because (if you don't look too closely) you'd think it was pruned in topiary style. The reality is that early blight foliage removal inadvertently results in this form. "Health Kick" was a spur of the moment pick at the greenhouse this spring. While it's more susceptible to early blight than the older "Celebrity" tomatoes I grew, I was able to harvest over 30 Roma tomatoes from one plant before early blight won. All Roma tomatoes have a natural resistance to late blight. So for now at least, I know I'll plant another Roma tomato and have time to see if my attitude changes about growing the others over the coming winter.







Topiary tomato - Early Blight on Roma tomato