Plant oats as a garden cover crop

It’s not your imagination, the growing season is winding down early this year. The excessive rain and cooler than normal temperatures in our area have combined to make it a challenging season for many garden plants especially the warm weather crops like tomatoes or peppers.

Farmers are noticing it too. Many field crops never fully recovered from poor start of the season and are showing signs of maturing early. As a result there may be a reduction in yields as well.

Certain beds in my garden are already kaput. But there is a silver lining in that. It gives me a chance to plant a green manure crop, which I don’t often get to do.

The terms green manure and cover crop are basically synonymous. Green manure is a crop that will be turned over into the soil while still growing, a cover crop may or may not be turned into the soil right away.

These types of crops are great for recovering soil nutrients from the soil and holding them until next year’s planting season. Some soil nutrients such as nitrogen are easily washed down into the soil profile by fall rains or melting snow putting them out of reach of most garden plants. Much of that valuable garden nutrients that you worked so hard to build up could be lost.

Multiply the nutrients over hundreds of acres and you can see why farmers use cover crops to save money and protect the environment at the same time. Nutrients that stay in the field will not get washed into steams and rivers where they end up being a source of water pollution.

In other words, green manures effectively “mop up” nutrients and hold them in place until they are needed next year.

In a garden situation, the biomass that a green manure crop adds to the soil may be more valuable than the nutrients they conserve. You really can’t have too much organic material in garden soil.

A cover crop also provides a better habitat for soil microbes to flourish as opposed to bare soil.

Planting cover crops is a fairly advanced technique for home gardeners even though it is very effective for both vegetable and flower gardens.

If this is your first time planting cover crops, consider oats, yes the same plant that is harvested and used for making your breakfast cereal. They make a very effective cover crop.

This time of the years we are looking for a plant that will make quick growth and oats fit the bill. Even though they grow quickly, they should be planted very soon.

The other big advantage that oats have is that they will die over winter leaving a mulch on the soil surface that can be tilled in next spring. That also eliminates the possibility that they may become a weed in your garden. I’ve had winter wheat come up in the spring — seeds from straw mulch — and before I knew it they became a problem. Have you ever tried to pull up a well established clump of wheat? They’re pretty tough plants.

Planting oats is much like planting grass seed except the seed is much larger.

 

Oats ready for planting. Note that they still have their outer covering, the hull surrounding the seed
Oats ready for planting. Note that they still have their outer covering, the hull, surrounding the seed

Sow oats at a rate of two or three pounds per 1000 square feet about an inch deep. Farmers use an implement called a seed drill to plant oats. The easiest method for a gardener is to broadcast the seed by hand, then till very shallowly with a tiller. Finish off by lightly pressing the area down so the seeds make good contact with the soil.

Farm supply stores sell oat seed however you may have to go online to buy small quantities.

Bob

Flowers on elephant ears — colocasia

I’ve been growing Elephant ears — Colocasia esculenta — for many years. Over that period of time I’ve rarely had them bloom. They just don’t set flowers very often.

Normally when plants blossom, it means they are all set to produce seeds. Colocasia, however has been cultivated for so long, that it no longer is able to produce seeds and relies on people to reproduce. In tropical regions, people plant the underground corms like we would plant a flower bulb here in Michigan.

Colocasia is a dramatic addition to the landscape with it’s huge leaves that easily grow to three feet long in Michigan. In it’s native area in the tropics the leaves can measure six feet in length.

People in the tropics don’t grow them for their landscape, instead they eat them. There, colocasia is called taro and is a major food crop where it is used like we use potatoes here. Millions of tons of taro are harvested each year.

One winter, many years ago, I had a recent immigrant from the south Pacific visit the greenhouse where I was growing dozens of colocasia in pots getting them ready for planting out into the landscape. She recognized them immediately and asked me if I was growing them for harvest. I told her they were for planing out in the landscape as a decorative plant. She laughed and thought that was quite funny!

 

The flower bud on my colocasia is ready to open.
The flower bud on my colocasia is ready to open.

My blooming colocasia was one that I stored in my semi-heated garage over winter. I kept it in its pot and let the soil dry out. I watered it once in a while.

The plant went dormant and was exposed to some cool temperatures for extended periods of time but it never got much colder than the lower 40’s. The only light it got was low, indirect sunlight from a small garage window.

I have a theory that stressing the plant somehow triggered a flowering mechanism. The other colocasia I had bloom was about 12 years ago and that plant was stored over winter much the same way.

I’d be interested to hear if any readers have had similar experiences with their colocasia.

Bob

Medicinal garden growing at Matthaei Botanical Gardens in Ann Arbor

Not long ago growing culinary herbs in a home garden was regarded as an eccentric thing to do and only the most adventuresome gardeners grew medicinal herbs. Things have changed and more gardeners than ever are growing herbs of all kinds.

Seeds for medicinal herbs are readily available in catalogs and online stores making it easy to get started with medicinal herbs.

There are plenty of books and online resources available for anyone interested in growing medicinal herbs but nothing can replace seeing it first hand.

For a wonderful introduction to the world of medicinal herbs visit the Medicinal Garden at University of Michigan Matthaei Botanical Gardens. The folks at Matthaei have collaborated with the U of M College of Pharmacy to develop this garden. There you can see many different medicinal plants growing.

Over forty percent of medicines are derived from plants.
Over forty percent of medicines are derived from plants.

The garden is not organized by genus and species as botanists like to do but rather by human body systems: respiratory, gastrointestinal, cardiovascular and more.  Other areas of the garden are devoted to disorders such as diabetes, infectious diseases, cancer, etc.

Matthaei Botanical Gardens is located near Ann Arbor at 1800 North Dixboro Road, a half mile or so south of Plymouth Road. They’re open daily from 10 am to 8 pm during the summer season.

Bob

 

Mud dauber wasps are busy

This week while going through some items in a storage shed, I came across a beautiful dried ball of mud inside an antique trunk. It was the nest of a wasp known as a mud dauber.

When we think of wasp nests, usually the first thing that comes to mind is the papery nest of the paper wasp or the football-shaped nest of hornets. Mud daubers build their nests out of mud. There is plenty of mud for the wasps this summer because of the regular rains we’ve been having.

Mud daubers are not social insects like paper wasps and the others. Instead, they spend their lives as single, solitary insects. They do everything by themselves including, building a nest, laying eggs and collecting food for their young.

There are many different species of mud daubers in Michigan, this one is called the “black and yellow mud dauber”.

The adults look similar to the more common social wasps but are larger and have exaggerated features like the thread-like connection between their abdomen and thorax.

The female mud dauber builds the nest by collecting mud along the edge of puddles. Using her mouth parts, she rolls the mud into a ball then lifts it into the air and carries it to the nesting site. There she adds the mud to her nest, building rooms or cells for her young. Each cell is big enough for one young mud dauber.

The entrance to the nest is sealed shut. She must be out working collecting mud or food for her young.
Here she is, busy plastering new mud on her nest.
IMG_3026
The entrance to the nest is open, she must be nearby.

 

While the female is away from the nest gathering mud or foraging for food, she temporarily closes the entrance to her nest to keep predators away from her young. During that time, the daubers are in the larval stage of their life cycle.

The female also packs away food for the developing larvae by placing insects or spiders into each cell so the larva has enough food in its cell to carry it through its growing stage. Some types of mud daubers only prey on spiders while others prefer caterpillars or other insects.

The entrance to the nest is closed shut. Mama mud dauber must be out collecting more mud or insects for her young.
The entrance to the nest is closed shut. Mama mud dauber must be out collecting more mud or insects for her young.

The prey is only for the young though. The adults feed on nectar, honeydew from aphids or other sugary liquids. Sometimes you can spot them sipping sugar water from hummingbird feeders.

Unlike other wasps and hornets, mud daubers don’t defend their nests. They are not aggressive and rarely sting. Although if you try hard enough you can sometimes provoke one into stinging you.

According to one university website, some species “sing” while building their nest! Mine didn’t seem to be in a singing mood when I found her.

They are generally considered beneficial insects because they eat other insects. You could argue that the spider-eaters are not very beneficial because spiders eat insects too — that is unless you hate spiders.

Most of the time we don’t notice the daubers until they build a nest somewhere where we don’t want it. Some people destroy the nest as soon as they find them.

There seems to be a small industry built around exterminating mud daubers and getting rid of their nests. I prefer to let leave them alone and let them go about their business.

I’ve noticed other smaller species of mud dauber wasp around too. They are not shy and can be very annoying as they buzz around looking for small holes to use for building their nests.

Bob