Monthly Archives: August 2012

The Perfect Fungal Storm – Septoria Leaf Spot on Tomatoes

A few weeks ago the determinate tomatoes started looking very bad. More than half of the leaves had died on some of the plants; a couple of plants had lost all of their leaves. Tomatoes usually look a little beat up by late summer with some of the bottom leaves dying but it’s never been this bad.

There’s been a lot of talk about late blight but when I looked at the tomatoes I found that only the leaves were affected. I’ve seen late blight and when plants have it there are lesions on the fruit and stems. The stems and fruit of these tomatoes were fine. The only problem was that the leaves were dying.

Tomato Plants with Septoria Leaf Spot

With a little research I found out that the problem was septoria leaf spot, a fungal disease caused by the fungus Septoria lycopersici. The initial symptoms of this disease are small spots on the lower leaves of tomatoes. If the conditions are wet, the fungus can form fruiting bodies which produce spores. The spores are spread by rain and can defoliate the plant if the conditions are right. It’s obvious that the conditions were right for a bad case of septoria this year so what were those conditions?

The first condition was that the tomato plants this year were huge. I planted Pony Express, which is a determinate tomato, and the plants were the biggest I’ve ever seen and each was full of fruit. As an habitual “underfertilizer,” I had made the decision to fertilize a little more this year. It’s obvious that the tomatoes liked the additional fertilizing.

Septoria Leaf Spot in All Stages – unaffected leaves, leaves beginning to show spots and leaves that have died from the fungus

The second problem was that the plants were so heavy with green tomatoes that the tomato cages I got at the local big box store weren’t able to stand up to the weight of the plants. A couple of wind storms right before the fruit started to ripen knocked over most of the cages. As a result, the plants were jumbled together and no longer elevated above the ground.

The final issue was that after a dry June and early July, the rain started to fall. During the middle of July it rained a little every few days and when it wasn’t raining, it was hot and humid.

Put these three conditions together and you have the perfect storm for an outbreak of septoria. The large, collapsed plants no longer had good air circulation. Also, the septoria spores, which are found in the soil and on the infected leaves, could now splash on most of the leaves of the plants. Add to these conditions a little rain, heat and humidity and it’s no wonder that the tomatoes look so bad.

While I doubt I can prevent septoria completely, I am already making some plans for next year to limit its damage. While I have no control over the weather, I can make sure that the plants remain above the ground and have good air circulation. I plan to make sure that the tomato plants are spaced properly and have some sturdy support. I read about a way of supporting determinate tomatoes called the Florida weave that’s used by professional growers – it could work well. I might also make my own cages out of some sturdier material. I have the winter to think about this and plan for the coming year.

While the septoria has done a good job of damaging the tomatoes, I’ve still had a good harvest. There have been more than enough tomatoes for freezing and canning. So while no one wants diseases in the garden, septoria is one that isn’t too bad. It only affects the leaves and, with proper growing conditions, it can be managed.

So here’s to next year with tomatoes more widely spaced, more strongly supported and, hopefully, less affected by Septoria lycopersici.

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Curcuma Inflorescence and Flowers

Curcuma Inflorescence

The curcuma experiment is going very well. Those strange little rhizomes are now in full bloom. Each one has  produced one flower and more flowers are forming.

But let me stop right there. What I just wrote isn’t technically true. To be botanically correct, I should have written that each curcuma rhizome has produced one inflorescence and that one inflorescence is producing dozens of flowers. What I refered to earlier as a “flower” isn’t a flower at all. It’s an inflorescence. An inflorescence is a group of flowers arranged on a stem. An example of a basic inflorescence is a hyacinth. Each of the star-shaped blooms is a flower but the entire stem of flowers is called an inflorescence.

Curcuma Flower

It wasn’t until the curcuma started to bloom and I looked more closely at it that I realized that I was seeing an inflorescence. The green and pink parts of the inflorescence aren’t petals of a flower but bracts – modified leaves. The true flowers of the curcuma grow out of the area where the bracts and the stems meet and they’re small white and purple blooms. The inflorescence of the curcuma lasts for at least a month; the flowers only last for one day. In this plant, the flowers are insignificant but the inflorescence with its bright-colored bracts is what make it a showstopper.

Poinsettia Flowers

The most well-known plant with showy bracts and small flowers is the poinsettia. What is usually called a “flower” in the poinsettia is once again an inflorescence. The showy red, pink or white “petals” are really modified leaves. The flowers are the small green and yellow clusters at the center of the bracts. The flowers themselves only last for a few weeks while the bracts can remain in good condition for months.

Right now the curcuma is flowering but not in the way I originally thought. I had assumed that the large, pink structures were flowers. They’re not. I have to look closely to see the true flowers of the curcuma. But let’s be honest here – while I know the structure growing above the curcuma leaves is an inflorescence and the pink “petals” are really bracts, on most days I’m just going to call it a flower!

The Baldfaced Hornet

About a week ago I was checking on the two asian pear trees that are growing in the yard to see how soon I could start harvest pears. I was surprised to see that a number of the pears had been partially eaten by a wasp or hornet that I’d never seen before. It was a very handsome insect – that is if you’ll allow insects to be called handsome – with a black body and white markings.

Baldfaced Hornet on an Asian Pear

After a little searching, I learned that these pear eaters are baldfaced hornets (Dolichovespula maculata). They get their name from the white markings on their heads. While they’re called “hornets,” these insects aren’t true hornets but are instead yellowjackets.

Baldfaced hornets are found in all of North America and live in papery nests that are found in trees or bushes, though they can be built under the eaves of building. These nests can be up to 2′ high and 18″ wide. At the center of the nest is the queen and the mission of all of the workers is to feed the larva. In the spring and early summer baldfaced hornets focus on finding protein sources for the developing larvae. The primary sources of this protein are flies, other yellowjackets and a variety of other insects. As the season goes on, there are fewer larvae to fed so the baldfaced hornets turn to nectar and other sources of carbohydrates.

Baldfaced Hornet

It was the free source of carbohydrates that drew these insects to the asian pears. The fruit had just begun to ripen but it was ripe enough for them. While I don’t like losing fruit to the baldfaced hornet, after a season of them killing flies, yellowjackets and other insects, I’m willing to overlook a few lost pears.

Baldfaced hornets can sting and, like other yellowjackets, they have a smooth stinger so they can sting repeatedly. While there is some danger of being stung, the baldfaced hornet is in truth a beneficial insect. It kills unwanted insects and, when it’s searching for nectar, it helps to pollinate flowers.

On the day I noticed this insect I harvested all of the undamaged pears. Since that time I haven’t seen another baldfaced hornet. But I’ll be expecting their return next summer to let me know when the pears are getting ripe.

Home-Grown Garlic

Only in the past few years have I been growing garlic. I never thought it was worth growing this crop until I tried it. Once I started using home-grown garlic, the bulbs in the grocery store just couldn’t compete.

Garlic Plants in Early May

Garlic is one of the easiest vegetables to grow. This relative of onions and leeks has very few pests, isn’t bothered by rabbits (!) and doesn’t need an overly fertile soil to grow well. The only thing it does require is well-drained soil. If water puddles on the ground were garlic is growing, the plants will likely die.

When you grow garlic you have two kinds of garlic from which to choose – hardneck and softneck. Softneck garlic (Allium sativum subsp. sativum) is the kind of garlic you find in the grocery store. Each head has  6-18 cloves in several layers. Softneck garlic tends to mature earlier than hardneck varieties and usually has the best storage qualities.

Hardneck garlic (Allium sativum subsp. ophioscorodon) produce 5-10 cloves per head. The cloves grow in a single circle around a central woody stem, hence the name “hardneck.” Hardneck garlic has a shorter storage life than softneck garlic but is often hardier than softneck varieties.

Duganski Hardneck Garlic – note the central woody stem

I grew both kinds of garlic for a few years but now I just grow hardneck varieties. The cloves of hardneck garlic are so much bigger than those of softneck and, since I use a lot of garlic, bigger is better! I’ve had no trouble storing hardneck garlic – I use all of the garlic before it starts to go bad.

Unlike most other vegetables, garlic is planted in the fall. Here in PA I plant it in the middle of October. I break the heads into cloves and plant them 6″ apart and 2″ deep. I then cover the area with straw to control weeds Within a few weeks the garlic sprouts and grows for a while until the cold weather comes. I don’t worry about additional mulching for the winter but in colder areas it’s probably a good idea.

When the weather warms in the spring, the garlic is ready to grow. I find that the plants keep growing until mid-July. You know it’s time to harvest garlic when only a few of the leaves on the plants are still green. Each leaf represents a layer of covering on the head of the garlic. If you wait to harvest the garlic until all of the leaves are brown, the covering of the head is likely to be gone when you dig the plants. As a result the cloves will be exposed to the soil and won’t last very long. If you dig the plants when a few leaves are still green, the heads will have a nice covering. After allowing them to dry in a protected spot (I put them in the garage), the tops can be cut off and the heads put into storage.

You can plant cloves from the garlic you harvested but there’s a chance that they might have been infected with virus during the growing season. If you plant virus infected cloves, next year’s harvest will be much smaller. To me, it’s just easier to order new, certified virus-free garlic each year.

Most seed companies offer garlic but I’ve been impressed with the variety of garlic offered by the Territorial Seed Company. They have over 15 kinds of hardneck garlic. My favorite to grow is Duganski because the heads are huge and the flavor is great. But each year I also get another variety to grow and compare with the Duganski. None of them have disappointed me and I look forward to trying the varieties I haven’t grown.

If you’re a garlic lover and want an easy to grow crop, you can’t go wrong with garlic. Just know that once you start growing it and see the size of the heads and taste the flavor of the cloves, you’ll probably never again plant a garden that doesn’t include garlic!

Perennial Hibiscus

Every year I’ve gotten an hibiscus to grow in a pot on the patio. I liked the fact that you could get plants with orange, yellow, red, pink or bicolor blooms and that some of them were double. The thing I didn’t like was the price – they were always at least $15.

For years I’ve been growing tropical hibiscus. The plants are nice and the 4″ blossoms give the garden a tropical feel. But, unless you’re willing to bring them inside and nurse them through the winter, they’re a one season plant.

But now I’m hooked on a different kind of hibiscus. Instead of the tropical plants, I’ve started to grow perennial hibiscus. These plants will survive the winter up to zone 5 (I’m in zone 6). After a killing frost, the plants die back to the ground until the next growing season.

Southern Belle Hibiscus

Perennial hibiscus is easily grown from seed. Last year I planted some seeds of the variety Southern Belle in the summer, overwintered the plants in a vacant spot in the vegetable garden and then transplanted them around the pool in the spring. The plants are growing well even though the soil isn’t the best. They can get up to 5′ tall but right now the plants are about 3′ in height. I expect them to get larger in the coming years.

As one who’s been growing tropical hibiscus, the blossoms of perennial hibiscus are just amazing. While there are only three colors in perennial hibiscus (red, pink and white) and all of the blooms are single, the 10″ dinner plate sized blooms are huge. They make such a bold statement.

Perennial Hibiscus Close-Up

Besides the Southern Belle plants, I also started some seeds of Disco Belle (a smaller perennial hibiscus variety… and who comes up with these names?!) inside this spring. I wasn’t too hopeful when I transplanted the seedlings into a large container in early May – the plants were about 3″ tall with 6-8 small leaves. But once they got established, the Disco Belle plants took off. They’re now 2″ tall and filled with 8″ blossoms. While these plants will come back next year, if you start the seeds early you can also grow perennial hibiscus as an annual, especially for container gardens.

The only thing I’ve learned to be aware of is that perennial hibiscus are one of the last perennials to emerge from dormancy in the spring. All of the other perennials will be growing before the hibiscus has even begun to send up shoots. As all the other perennials started to grow, I wondered if the Southern Belle plants in the garden had died. They hadn’t; all they needed was a little more time.

I’m hooked on perennial hibiscus as a garden and container plant. From a $3.50 packet of seeds you can easily grow a half-dozen plants that will be covered with huge flowers in the heat of summer. While I miss some of the colors of the tropical hibiscus plants, the perennial hibiscus provides a lot more bang for the buck!