Look out for cabbage worms

Earlier this week I spotted some small, white butterflies flitting around in our garden.  They were the easy to recognize adult stage of the imported cabbage worm larva. Now, a few days later,their larvae are voraciously eating our cabbage.

Typical signs of cabbage worm infestation: holes in the leaves and caterpillar droppings called "frass".
Typical signs of cabbage worm infestation: holes in the leaves and caterpillar droppings called “frass”.

Curiously, I haven’t seen any on the broccoli or kale yet, but they will show up there soon too. These pests eat any and all plants in the cabbage family including broccoli, cauliflower, kale, turnip and rutabaga. They are said to attack radishes as well but I’ve never seen it in all my years of gardening. Maybe it’s because our local population would rather eat the other plants if given the choice.

BTW, it’s not the baby caterpillar that makes the choice what to eat, it is its mother. The female butterfly flies all around looking for the ideal spot to lay her eggs so her offspring have the best food to eat. That way they can grow up to be big and strong and healthy. That is good for the cabbage worms but can be disastrous for a garden.

Farmers know that within days a few cabbage worms can chew so many holes into a cabbage that it will be unfit for market. Even in a home garden cabbage worms will ruin large portions of a cabbage.

There are a couple of different species of cabbage worms in our area, one is the imported cabbage worm, the other is the cabbage looper. They are both green and color and do the same damage. Imported cabbage worms are very slow and sluggish when they move. Cabbage loopers move along like inch worms.

If left alone, this young imported cabbage worm will quickly grow and cause lots of damage.
If left alone, this young imported cabbage worm will quickly grow and cause lots of damage.

Both species of cabbage worm are easily controlled by insecticides labeled for chewing insects on vegetables. Bacillus thuringiensis, or Bt, is a favorite worm killer among organic gardeners. It is made up of spores from a bacteria that infects only caterpillars and is harmless to other insects.

Controlling them now while they are still small is much easier than waiting until they get bigger and really start chewing away large chunks of your crop.

Bob

Flea beetles causing damage in vegetable garden

We’re seeing the first flea beetles in the garden this season. These tiny pests can cause a lot of damage to small plants if they’re not knocked back early on.

Usually the first thing you see when flea beetles enter your garden is the distinctive chewing pattern they make on the leaves and not the beetle itself. Flea beetle damaged leaves are riddled with small holes.  Imagine what would happen if a garden fairy took its tiny shotgun and blasted away at the leaves, that’s what flea beetle damage looks like.

The beetles themselves are black and less than 1/16″ long. They sometimes will jump, sort of like a flea, when disturbed.

Like many insects, they have their favorite foods. In our garden eggplant and potatoes are the first to be gnawed followed by tomatoes then all of the other vegetable plants.

Vigorously growing plants can usually shrug off a flea beetle attack.
Vigorously growing plants can usually shrug off a flea beetle attack.

The greatest danger to the garden is when the plants are small and growing. At that young stage flea beetles can stunt or even kill plants. As the plants get larger, they can sustain much more feeding by the beetles.

Fertile soil and timely watering will help plants stay healthy and grow past that vulnerable stage.

A homemade concoction made from garlic and hot peppers will fend off the beetles for a while. Take a half dozen cloves of fresh garlic and crush them up. Add the garlic along with a tablespoon of dried, crushed red pepper to a quart of water. Let it steep for a couple of days. Strain the mixture. Spray it onto your plants every three days or so to chase away the flea beetles.

If you have a really bad infestation or a big garden, you can use any garden spray or powder that is labeled for killing beetles in the vegetable garden. Organic gardeners can use that old stand-by rotenone. Pyrethrum or spinosad, both considered organic insecticides, are good too.

Bob

Thin vegetable plants for best results

One major job in the garden this week is thinning our vegetable seedlings. It’s one of those things that is hard to do sometimes. Plucking all those little seedlings after waiting so long for them to germinate seems drastic but it needs to be done.

Most of us have no compunction when taking out weed seedlings but have very mixed feelings when it comes to removing vegetable seedlings. After all, we paid good money for those seeds and now we’re going to pull them out just as they are getting going?

When growing too close together, vegetable seedlings compete with each for nutrition, water and sunlight just like weeds.

Beet seedling can be moved and transplanted to a different part of the garden after thinning.
Beet seedling can be moved and transplanted to a different part of the garden after thinning.

Over crowded seedlings will grow and produce but will never live up to their full potential. Gardeners who have never thinned vegetable seedlings before are often shocked at the improvement that happens the first time they thin. Vegetables are larger in size, better quality and have a higher total yield.

Seed packs have information printed on them that give final plant spacing which is very helpful to beginning gardeners. Experienced gardeners are able to estimate spacing by envisioning the plant when it is full size, then leaving the right amount of space between seedlings.

Most thinned seedlings can be transplanted to another part of the garden, the exception is carrots. A carrot’s shape is determined by its main taproot. If the root gets bent during the transplant process, the resulting carrot will develop that shape defined by the bent root.

Bob

Great tasting brussels sprouts for Christmas dinner thanks to El Nino

I had someone ask me a while back when she should pick her brussels sprouts. Most experienced gardeners will tell you that Brussels sprouts are best after a hard freeze, and that is certainly true.

Cool temperatures help the sprouts develop a complex flavor with more sweet notes and less bitterness.

We’ve had a hard freeze several weeks ago — the one that put an end to the gardening season. That was probably enough to start improving the flavor.

Brussels sprouts can tolerate fairly cold temperatures. Many years, I’ve been able to leave the plants out in the garden at least until Thanksgiving and during strong El Nino years, until Christmas. Since a strong El Nino has developed, it looks like we will have one of those seasons where brussels sprouts can be left out in the garden until New Year!

This is important if you want to get the absolute best tasting brussels sprouts possible. Brussels sprouts start losing their flavor just three days after picking. On the other hand, the flavor keeps improving as long as the sprouts stay on the plant. So you can see the advantage of leaving the sprouts on the plants until you are ready to cook them.

There are millions of people who will never eat brussels sprouts because they were forced to eat them when they were a child. They wonder why they were ever invented in the first place.

At one time, brussels sprouts were always picked by hand and those old commercial varieties tasted halfway decent. Then in the 1970’s and 80’s machines were engineered to harvest the sprouts. That meant physical changes had to be made to the brussels sprout plant itself in order to accommodate machine harvesting. In the rush to breed machine harvest-able plants, the cost came down drastically but the flavor was lost in the process. They became strong-flavored and bitter.

Things have changed in the past 20 years or so. Big improvements have been made by plant breeders to improve the taste of brussels sprouts, they’ve gained back the flavor that was lost during the early years of mechanization. It may be time to re-try brussels sprouts if you haven’t tasted them since you became an adult and now make your own food decisions.

This past season was cool enough to enhance brussels sprout growth. Ours grew nearly four feet tall.
This past season was cool enough to enhance brussels sprout growth. Ours grew nearly four feet tall.

Pick brussels sprouts by snapping them off the plant with a twist. Remove the outer layer of leaves. Some gardeners dig up the whole plant and save the sprouts on the stalk to pick off later.

The best way to cook brussels sprouts is to steam them until they are tender enough to be pierced by a fork, about 7-14 minutes. Some people cut a small “x” in the bottom of each stem to help them cook more evenly. Overcooked sprouts turn mushy and loose flavor and nutrients.

I plan to leave my plants in the garden as long as possible this season. And if very cold weather ever arrives, I’ll pick the remaining sprouts, blanch them and store them in the freezer.

Bob

 

Wet weather now may contribute to gnarly tomatoes later

Heirloom variety 'Stupice' tomato flowers.
Heirloom variety ‘Stupice’ tomato flowers.

I don’t have to tell you we’ve had more rain than usual this gardening season in southeastern Michigan. Some locations, like my garden, have had significantly more rain than the official reporting stations because of localized heavy down pours. Don’t be surprised if you see a higher proportion of misshapen tomatoes in your garden this year be cause of this.

If you’ve grown tomatoes for any length of time, I’m sure you’ve picked your share of distorted tomatoes.

You may remember from your high school biology class that a tomato develops from the female parts of  a flower — the ovary and ovule. Under good weather conditions the tiny, newly formed tomato grows and matures normally. But when the weather doesn’t cooperate, tomatoes can develop a number of different problems.

Tomatoes that have distorted areas with rough, brown edges are called “catfaced”. Although they are safe to eat, they don’t look very attractive. Catfacing is most often caused by flower petals sticking to the ovary just as the tomato begins to form. Rainy, damp weather keeps the petals from drying completely and separating from the rest of the flower.

“Zippering” is another related condition caused by damp weather. The symptom is, a long, rough, thin brown scar running longitudinally — north pole to south pole — on the skin of a tomato. It’s caused by the anther, the male part of the flower, adhering to the young fruit as it grows.

Sometimes an open locule forms along with zippering. A locule is a chamber inside the ovule that produces the fruit part of the tomato. An open locule is also called an “open hole”. It shows up as a dry, brown hole or depression on surface of the tomato.

Those over-sized, distorted tomatoes that look like two or more tomatoes merged into one, are also caused by poor weather during flower development.

Some varieties are more prone to these disorders than others — the “Beefsteak” varieties being one common example.

I should stop here and mention “blossom end rot”. It is not related in any way to these disorders but is caused by inefficient movement of calcium inside the tomato. That is a discussion for another blog.

Distorted tomatoes can also be caused by high soil nitrogen, excessive plant pruning, exposure to herbicides and tomatoes rubbing against one another.

As the weather straightens out, tomatoes forming later in the season will have fewer catfacing and zippering symptoms at maturity.

Bob

Double — even triple– your pepper yields

If you’ve never had much luck growing peppers, you can vastly improve your pepper yield by doing a bit of extra work now before the plants go into the garden. The secret is to use plastic mulch.

In the past I’ve experimented with several colors of plastic mulch: clear, black, red, blue and silver. All of them showed a huge improvement over organic mulch or no mulch at all.

Using plastic mulch is not a new concept, it’s been around for decades. Commercial farmers and researches have improved yields even more than double.

There are several reasons why plastic mulch works so well. The most obvious is reduced weed competition. Plastic mulch prevents nearly all weeds from growing by blocking sunlight to the soil. The only weeds that you have to contend with are those that sneak up through the hole made in the plastic for planting. The exception is clear plastic mulch. It lets sunlight through allowing weeds to thrive under the greenhouse-like conditions.

Whenever you hoe or till around plants, no matter how careful you are, valuable surface roots get cut. Since plastic mulch keeps weeds from growing, there is no need for hoeing or cultivating except in pathways between the rows of mulch.

Soil temperatures are warmer under plastic mulch which is important in a relatively cool environment like Michigan. Peppers are warm season crops that respond well to warm soil temperatures. Organic mulches on the other hand, tend to keep soil temperatures cool.

Oxygen is critical for plant roots. Garden soil under plastic stays loose, leaving space between soil particles so that air can move. This creates a better environment for plant roots and soil microbes to do their job.

Bare garden soil loses a lot of water through simple evaporation. Plastic mulch keeps the soil from drying out allowing more water for the plants to use when they need it.

Some plant diseases are spread by rain or irrigation water splashing soil up onto the plant. Plastic mulch keeps plants clean and less susceptible to disease infections.

Carbon dioxide is produced in the soil and is a normal part of the soil dynamic.  On bare soil it diffuses directly into the air. Since gases can’t pass through plastic mulch, carbon dioxide tends to collect in very high concentrations underneath the plastic sheet. It can only escape by moving through the planting holes resulting in very high levels of C02 right at plant level where the plant can efficiently use it for increased photosynthesis producing higher yields.

Black is the default color of plastic I use in my garden. Mainly because you can find it just about anywhere, although I’m seeing more red plastic around lately. Also, black plastic is available in heavier grades than the colors allowing you to use it for more than one season if you want. I never use clear because of the weed problem I mentioned earlier.

Heavier grades of plastic mulch can be saved and re-used the next year.
Heavier grades of plastic mulch can be saved and re-used the next year.

This may sound obvious but, lay your plastic before planting, it will be much easier to transplant through holes in the plastic. I had an assistant years ago that transplanted the plants first and then tried to install the plastic. He got it to work but it was a chore.

It’s important that the surface of the planting bed is smooth and flat, sloping slightly so rain water can run off.  Rake out all debris and don’t step in the prepared soil.

Farmers use special machines to lay plastic in their fields but we don’t need anything like that in a home garden. I just stretch a string where I want the edge of the bed to be and dig a trench. I unroll the plastic and bury one edge with soil. Then I measure the width I need for the second trench — allowing for covering the opposite edge — stretch the string again and dig my second trench. A 48 inch wide roll gives me a planting bed just over three feet wide.

I cut an “X” through the plastic where I want the plants to go and transplant through the cut.

It takes some time to properly prepare the bed and install the plastic but you will be amazed by the results.

Bob

Snow cover helps plants through harsh winter

Our second bitterly cold winter in a row is finally over. Even though this winter was not as cold as last year’s, it still made the record books as one of the top twenty coldest. It’s kind of surprising to me how quickly it ended. Just a few days of moderate temperature erased the snow.

The plants in our area look to be in pretty good shape despite those cold temperatures. We can thank the continuous blanket of snow that was covering the ground all winter.

Snow is nature’s insulator. I’ve heard people say they were worried because snow would freeze their plants. I’ve had to point out to them that snow is a gardener’s best friend , especially if you have perennial flowers and small fruit such as strawberries.

Farmers who grow winter wheat — which is planted in the fall — pray each year for snow cover so their wheat crop is not damaged by exposure to cold temperatures and desiccating winter winds.

Despite the fact that I neglected to mulch my strawberries as I usually do, they look to be in great shape.

The garlic I planted last fall looks good too. There was no covering on those either except what nature provided in the way of snow. I got lucky this time skipping the mulch, I don’t plan on ever taking a chance like that again.

The mud season around here was pretty short too, it lasted only a few days. The mud I’m talking about is that mud that forms when the surface layer of the soil thaws but the lower layers are still frozen. That surface water has no where to go so just turns into mud especially if poultry or livestock are walking over it.

Since the soil was not frozen very deep around here — again thanks to the continuous snow cover — it was able to thaw out very quickly.

One other surprise I found was a couple of rows of spinach that were still green and beginning to make good growth. Without that snow, they would have been frozen out way back in November.

The snow cover provided plenty of protection for a small row of spinach.
The snow cover provided plenty of protection for a small row of spinach.

It looks like we’ll be eating an early salad from the outdoor garden this year.

Frosty temperatures can enhance lettuce taste

Our recent frosts have put an end to all of the warm season vegetable crops like tomatoes, peppers and squash.

The cool weather crops on the other hand are still hanging in there, even though the colder temperatures have slowed down their growth rate.

The flavor of leafy vegetables, like lettuce, cabbage, Brussels sprouts, kale and the like, is enhanced by light to moderate frosts. Root crops like carrots, and especially parsnips, sweeten up after exposure to cold temperatures.

Cold temperatures can enhance lettuce flavor.
Cold temperatures can enhance lettuce flavor.

The mechanism behind this phenomenon involves plant carbohydrates. Starches and sugars are different types of carbohydrates that are present in plants. When the plant is exposed to cold temperatures the starches get converted into various sugars that sweetens the flavor. This is the main reason why you should never keep potatoes in the refrigerator, it is the starches that give potatoes their distinct flavor.

Lettuce, cabbage and kale will eventually winter kill as the  season progresses. It takes quite a bit to kill Brussels sprouts, they can survive well into November getting more flavorful with each frost but they too will eventually freeze and die back.

Bob

Cool weather crops for winter harvest

My seeds are planted for my winter vegetable crop.

We have a small, unheated greenhouse — sometimes called a high tunnel — that I built last year out of salvaged parts. That’s where I sowed my seeds. In our climate, most winters are too harsh for plants to survive without some kind of protection.

In years past I’ve harvested winter produce from simple homemade cold frames made from window sash, low plastic covered tunnels and other kinds of structures. The secrete is to make sure the structure gets adequate sunlight and that it is air tight to keep frigid winter drafts from freezing the plants.

I was able to plant the entire floor area of the greenhouse with spinach, winter onions, radishes, beets and a couple of different types of lettuce — all cool weather vegetables. The seeds were left over from our spring crop.

Part of the winter greenhouse crop.
Part of the winter greenhouse planting. It will provide enough salad greens to supply us during the winter.

I’ve tried setting out transplants late in the season, they just don’t seem to be as hardy as plants grown from seed in place.

When the really cold weather hits, those plants will hardly grow at all, even when protected inside a structure. By sowing seeds now, the plants will have plenty of time to get to a usable size before they go into hibernation. Once they are established they will become accustomed to the falling temperatures and will be more likely to survive.

Bob

Time to let heirloom beans mature into seeds

Earlier in the season I mentioned that we were growing a few heirloom bean varieties.

The results are in. It turns out that the differences between varieties were pretty dramatic. ‘Chabarowsky’ beans out-performed all the rest of the varieties by a wide margin.

The seeds germinated and grew vigorously in the dry sandy soil in that part of the garden.

Chabarowsky has a climbing habit which makes it a pole bean type. I grew ours on a length of farm fencing so they were very easy to pick.

The beans themselves, when I picked them at the optimum time for green beans had no strings in the pods. They were simple to prepare for cooking. The rest of the varieties all needed to be “stringed” first. To be fair though, all of these varieties are grown primarily for dry beans, so picking them for green beans was not the best use for them.

On the other hand Chabarowsky beans have an excellent taste when cooked green.

I’ve picked quite a few green beans from the vines, now it’s time to let them grow and mature into dry beans. It takes about six weeks from the time the beans are in the edible stage until they will be mature enough to harvest for seed or dry beans.

Chabarowsky bean pods can get a foot long or more.
Chabarowsky bean pods grow to a foot long or more.

Chabarowsky will eventually produce white beans that look kind of like over-sized navy beans. Even though the vines are loaded with pods, there’s no way they will produce enough to make more than one batch of bean soup. Most of the beans will be used for seed. I’ll save some for planting next year and share the rest. I am curious however, how the dry beans taste.

Even though the Chabarowsky variety did well in my garden with its sand and low pH, it may not perform well in someone else’s garden. That’s why there were so many different seeds saved and passed down by generations of gardeners. The best performers in specific locations eventually became heirloom varieties.

Bob