Plants have developed an number of different survival techniques that can give them advantages over other plants competing for the same growing space. For example, some plants have roots that produce chemicals that inhibit the growth of other nearby plants of other species. It’s a process known as allelopathy.
Black walnut trees are probably the most recognized allelopathic plants. Homeowners find that it’s impossible to grow many kinds of plants in the root zone of a black walnut tree. Although they work differently than black walnuts, many farm crops such as alfalfa, buckwheat, winter rye and others are alleopathic plants.
Sunflowers provide a wonderful backdrop in the garden as they tower over a space making them a favorite of many gardeners. What gardeners might not know is sunflowers are also alleopathic plants. Because they have the ability to suppress the growth of weeds, sunflowers and other plants are the subject of on-going research to develop organic herbicides for use in sustainable agriculture. Unfortunately, along with weeds, many kinds of garden plants are affected by sunflowers as well.
Until you know which of your plants can tolerate growing near sunflowers, the best thing is to grow them in a separate bed away from other garden plants.
As mentioned in an earlier post on this blog, I planted a fairly large plot of buckwheat adjacent to our vegetable garden this spring. The main idea behind planting buckwheat was to provide forage primarily for honeybees and for any other pollinators that might be around to take advantage of it.
As it turns out honeybees are in the minority. When surveying the buckwheat plot, I noticed for every one honeybee I saw there were ten or twenty other pollinators. They included butterflies, small wild bees, small wasps, many kinds of beetles, flies and hoverflies.
Hoverflies are especially good to have in the garden. The adult hoverfly is a very agile flyer able to hover in one spot then zoom away, stop on a dime and hover in place again — they can even fly backwards. They don’t have teeth or mandibles so they can’t chew or tear into things. Their mouth parts are spongy and are designed to soak up nectar and other liquids as well as picking up small particles such as pollen. That is why they’re so attracted to the buckwheat flowers.
Hoverfly larvae on the other hand are insectivores that eat small soft-bodied insects. In the garden that means mostly aphids, thrips, leafhoppers and scale. All four of these common garden pests have a stage in their lifecycle when they are soft-bodied.
After mating the adult female hoverfly buzzes around looking for a likely spot to lay her eggs, someplace where her young will have easy access to food. How does she know where the best spot is? Aphids and those other insects get all their nutrition from plant juices. They can only use part of the sugar in plant sap so they excrete the unneeded sugar as a syrupy liquid called “honeydew”. It’s the honeydew that attracts the female hoverfly: where there’s honeydew, there are insects for her young to feed on.
During the larval stage, each individual hoverfly will eat up to 400 aphids and other insects giving it the needed protein to go on to further development.
Since they are such good flyers, it’s very easy for female hoverflies to fly from the buckwheat to our vegetable garden and back again. The habitat that buckwheat provides enables the beneficial insect population to grow much larger than it would otherwise. That is a good lesson about the advantages of encouraging beneficial insects with plants instead of trying to maintain a garden in the middle of a sterile environment like a mowed lawn.
This is the time of the season when tomato plants start showing signs of disease infections, usually as different shapes and colors of spots depending on which particular disease has infected the plant.
Last week I took an informal survey of several varieties of tomatoes to see how each variety is holding up under early disease pressure. My MO was to look for leaf spots on the plants. I made no attempt to identify which disease was causing what spots. Then I ranked them on a scale of zero to ten depending how bad the plants looked. Zero meaning no spots were visible, ten meaning severe symptoms. No plants were bad enough to score what I imagined to be ten.
I didn’t count how many leaves were infected; or measure how many square centimeters were discolored; or brix levels of leaves; or levels of ethylene gas; or any other scientific criteria. Heck, I didn’t even alphabetize the list of varieties. I ignored any cultural differences such as mulch, staked or caged plants, planting history, etc. .Over half were heirloom varieties, some of those looked quite good compared to the modern ones.
I surveyed about fifteen gardens in two different locations about 20 miles apart. I made a point to look at them all the same day because twenty four or even twelve hours could mean the difference between no spots and spots. Here’s a chart of what I came up with:
Pink Honey Drip
Large Red Cherry
Pruden’s Purple, by far looked the best it has no spots and very vigorous leaves. Chadwick Cherry came in a close second. There were a few different beefsteak-type tomatoes that were not specifically tagged by variety but all of them had more advanced disease progression.
Keep in mind this is only a snapshot of conditions for one day. That could all change later on as the plants begin to get stressed by fruit production.
A couple of gardeners I know asked me why their cucumbers didn’t come up this year. Others have mentioned that their beans didn’t come up either. Was there something wrong with the seeds this year?
After inspecting a few gardens, it became apparent to me what was going on. In each case, there was a heavy infestation of striped cucumber beetles. They are voracious feeders and are always on the lookout for their preferred food, cucumber vines and related plants such as melons and other vine crops.
In those gardens, the beetles ate every plant they could find that tasted like a cucumber. The sprouts just emerging from the soil were particularly vulnerable which is why it appeared that the cucumbers didn’t come up — they ate every last bit of the tiny cucumber sprouts before the gardener knew what happened. And larger, young transplanted cucumber plants were well on their way of disappearing down the gullets of the beetles. When the vine crops were all gone, they moved over to the bean sprouts and ate those down to the ground. Even older bean plants had lots of holes in their leaves from the beetles.
Striped cucumber beetles are about a quarter of an inch long. They have bright yellow bodies with distinct black stripes running the length of their wings.
This was just the first wave of cucumber beetles, we can expect one or two more generations of beetles to show up later this season. This generation of beetles will lay its eggs at the base of the plants in the garden. Later they will hatch, feed on plant roots for a while then pupate and emerge as adults later in the season. The next generation of beetles will feed on the underside of the leaves and even chew gouges in the fruits.
Even more important, cucumber beetles carry and will spread bacterial wilt, a serious disease of vine crops. Infected plants wilt and never recover. There is no cure for bacterial wilt once it infects a plant. It’s very disheartening to see your cucumber vines grow and begin to flower only to lose them to wilt. So it’s a good idea take care of cucumber beetles as soon as you find them. Hand picking doesn’t work because they can get away too fast. Instead, apply an insecticide labeled for cucumber beetles, most garden insecticides are effective against them.
I have an area in the garden that I will not be able to plant this year. Instead of letting it stay fallow and grow weeds, I planted buckwheat. It’s something I’ve done through the years whenever I’ve been unable to use an area for one reason or another.
Buckwheat is a fast growing plant that will out compete most weeds. Planting buckwheat allows me to place-hold that unused garden area while reducing weeds at the same time. It also takes up mineral nutrients from that soil that are unavailable to other plants. Those minerals are incorporated into the growing plant. Eventually, I’ll cut down the buckwheat and till it into the soil. As it decomposes, all those minerals will be released back into the soil in a form that other plants can use.
Buckwheat is not an actual wheat at all. Wheat is a type of cultivated grass, buckwheat on the other hand, is a broad-leaf plant. While regular wheat forms inconspicuous flowers that are hidden, buckwheat grows a profusion of while flowers. Those flowers are very attractive to honeybees and other pollinators. The dark, strong flavored honey that results from buckwheat nectar is highly prized by some honey aficionados.
Many years ago when I first started beekeeping, that dark buckwheat honey was considered a low quality product. Now that has all changed and buckwheat honey is often sold at a premium.
Planting buckwheat is a simple process. Till the spot you’re planting, spread some seed over the area and lightly rake it into the soil. Figure on using a couple pounds of seed per thousand square feet. In a few days you’ll see the young buckwheat plants emerge from the soil. If after a week or so of growing, some of your planting looks a little thin, sow more seed to fill in the area. Buckwheat can cover a space up to ten inches in diameter but an open spot larger that a foot across will allow weeds to grow.
I’ll keep you updated on the progress the buckwheat makes through the growing season.
One of my lushest weeds in the garden right now is lambsquarters. The pure stands coming up in my beds make it look like I purposely planted them there as a crop.
I didn’t plant them but I sure am using them as if I did. Lambsquarters are the most nutritious plant that grows in the garden. It makes the “super-food” kale look like junk food by comparison. Well maybe not junk food, but it is much more dense in most minerals and vitamins on a gram per gram basis than kale. A serving of lambsquarters has more minerals, by far, than a serving of kale. But to be fair, kale has more vitamin C than lambsquarters.
If you like the textures and tastes of a wide variety of salad greens, you’ll enjoy lambsquarters. It sort of reminds me of chard but it has its own texture and taste profile.
Raw lambsquarters has a small amount of oxalic acid but so does kale, spinach, all berries and many other foods including chocolate.
This morning for breakfast I made myself a frittata with lambsquarters and feta cheese. The blueish green leaves turned a bright green after a few seconds of steaming. When added to my deep-yellow, free-range eggs it made an appetizing color combination. The feta cheese added a tasty balance to the earthy flavor of the lambsquarters. It’s my favorite breakfast ingredient this time of year, right behind bacon, sausage and hash browns.
I’ve written about lambsquarters before and will probably will do so again but that is because such a gift from the garden shouldn’t be over-looked just because it is a weed.
Don’t be lulled into a false sense of security though. It is still a weed, a very aggressive weed that’s easy to control when it’s small but can quickly get out of hand if you let it. In a couple of weeks you’ll be wishing you didn’t save that patch to use as a salad green. Get rid of it as it appears and don’t worry, more will sprout up through the season.
I saw my first Monarch butterfly several days ago. I know they were here much earlier because I found a caterpillar on my milkweed plants. That means there had to be a female butterfly around before that.
It takes around four days for a Monarch egg to hatch. The caterpillar stage lasts around a week and a half to two weeks. Since my caterpillar was almost fully grown, the female Monarch that laid his eggs arrived nearly two weeks ago. How did she sneak into the yard without me seeing her?
Most of my milkweed plants are on the verge of blooming. The plants are maturing and the leaves and stems are beginning to stiffen and get tougher in order to hold up the flowers and seed pods. Although female Monarchs will lay eggs on any milkweed, they prefer the more tender leaves toward the top of the plant.
A gardener I know suggested that I cut back my some of my milkweed plants to stimulate new growth and leaves. Theoretically, those new leaves would make my plants more attractive to the butteries than others in the area. I just snipped off the plant just above the existing leaves. That caused some milkweed sap to ooze out of the cut. That sap is poisonous and irritating so make sure you don’t in your eye.
This is the first time I’ve tried this with milkweeds. I’ll let you know how it turns out.
“You planted your tomatoes too close together.” Have you heard that from visitors to your garden? Not leaving enough space between tomato plants is one of the most common gardening mistakes. The good news is that it’s probably not too late to move them if you do it right away.
It’s so easy to look at those small tomato plants and forget how big they will get during the summer. Even after all these years of gardening I still have to resist the urge to plant them too close together.
Large commercial farmers who grow tomatoes for canning plant their tomatoes very close together. We often see them in double rows about 18 inches apart with the plants very close together in the row. The double rows are then spaced around four feet apart. Planting them like that allows farmers to get the maximum production from their land. Special varieties have been developed to allow them to be planted so densely. Those varieties also account for the difference in taste between tomato products. It’s why one brand of ketchup tastes different from another.
Home garden varieties won’t grow and produce well if grown too close together. Older heirloom varieties will take up much more space than more modern varieties. They’ll keep growing all season long and can get pretty big by the time the first tomato is ready to be picked. That type of growth is referred to as being indeterminate. I plant those varieties about four apart in cages and up to six feet apart if I let them sprawl over the ground without any support.
Plant breeders have developed tomato plants that will stop growing once they reach a certain size for their variety. Those are referred to as determinate, we used to call them “bush tomatoes”. Determinate types of tomatoes can be planted closer together, around three feet apart in cages.
Good air circulation reduces disease problems and adequate sunlight allows the fruit to grow and develop. I remember hearing a saying many years ago that went something like: “Plenty of air and light, grows tomatoes right”. Giving your tomatoes enough room to grow will provided them with the air and sunlight they need to thrive.
The rye cover crop I planted last fall made tremendous growth this spring. The plan all along was to till it into the soil before planting a week or so before planting.
Timing is important when it comes to tilling under a cover crop like rye. The plants grew and entered the “boot stage” of growth, forming flower/seed heads inside the stalk. This is the ideal time to till rye into the soil. At that stage the plants are about 20-24 inches tall.
I thought the garden was quite fertile, and it is, but the spots that received a little heavier application of compost last fall are much greener, taller and are developing seed heads earlier. It’s a good demonstration about the benefits of compost.
The plants were too tall for the rototiller to handle on its own. I had a couple of options, either kill the rye with an herbicide like Roundup, which is what most of the conventional farmers do, or mow it. Since I’m trying to keep it an organic garden, I mowed.
Twenty inches tall sounds like a lot for a mower to handle but rye is very tender and juicy in the boot stage — they are almost all water. If I had mowed it before the boot stage, the plants would have grown back just like a lawn. If I waited too much longer, the plants would have been tougher and drier as they begin to form seeds. That would have made it much more difficult to till and would leave too much coarse plant material in the soil.
Plant growth stage was not the only thing I was checking, I looked at soil moisture too. All the rain we had at that time left the soil temporarily saturated but it dried fairly quickly. Tilling a garden that is too wet destroys its soil structure negating most of the benefits that a cover crop provides. The rye along with winter freezing and thawing improved the soil structure by forming loose aggregates of soil particles leaving plenty of space for roots to grow.
Another very visible advantage to this cover crop was the lack of weeds this spring. By this time the garden would have been full of all kinds of broad leaf weeds and grasses. Dandelions would have come and gone by now. The rye did its job and out-competed virtually all other plants giving me a head start over the weeds this year.
The Matthaei Botanical Gardens – Nichols Arboretum annual Mother’s Day Plant Sale is coming up this weekend, May 13 and 14.
About three weeks ago I visited the Gardens and got a sneak peek at the plants growing in the greenhouse. I can tell you that these are no ordinary, anonymous plants grown by an impersonal factory growing operation. They are lovingly grown and tended by Adrienne O’Brien and her helpers right in the greenhouse at the Botanical Gardens. When I was there, the plants were still young but were growing strong and looked absolutely wonderful.
Now the plants are ready to go home to Mother’s house.
The sale runs from 10:00 am to 4:30 pm both days (9:00 am if you are a member). Matthaei Botanical Gardens is located at 1800 N. Dixboro Road, south of Plymouth Road, Ann Arbor.