The colder than normal April has been a topic of conversation with just about everyone. Mostly I hear people complaining about it but when I talk to people who spend a lot of their leisure time outdoors, the conversation gets much more interesting.
Fishermen I’ve talked to have mentioned how far behind their season is. Mushroom hunters are wondering about their upcoming picking season. Other outdoors people are saying much the same thing. As a gardener, I have to concur, we’re about two weeks behind normal. The agricultural weather people at MSU have measurements and statistics backing up observations made by us outdoors types. The statistic they look at is “growing degree days”.
The growing degree days system is a way of calculating when a crop should be planted and at what stage of growth it should be during the growing season. This is much more accurate than looking at the calendar and expecting “the corn will be knee-high by the fourth of July”. A month like the April we’ve been experiencing demonstrates just how inaccurate simply looking at the calendar date can be.
Plants require a certain amount of heat in order to grow and reach their different developmental stages. For example, corn seed germinates, then the seedling grows and forms leaves. The plant later forms silk and tassels out. After fertilization, ears of corn form and eventually ripen. A certain number of growing degree days will have accumulated at each one of these stages.
Insects, since they are cold-blooded, also require heat to grow and progress through their stages of growth: egg, larva, pupa and adult. Like plants, at each stage a certain number of degree days must have accumulated before that particular stage is reached. That gives farmers and gardeners a tool to help predict when an insect pest might arrive and cause damage.
So now that we are two weeks behind at the very beginning of the growing season according to the calendar, what does that mean for us in a practical sense? One way of looking at it is: insect pests have no choice in the matter. They are already two weeks behind in any development they might have made during a normal year and even further behind if this were a warm April. Gardeners will most likely be planting their gardens at pretty much the same time, say near the end of May. If the trend continues, conceivably it would mean gardeners will have a two week head start ahead of the insect pests.
It will be interesting to see how this cold start to the season plays out.
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.
Our mild autumn temperatures have accelerated the growth of fall-planted, over-wintering, cover crops.
Back in October I wrote about planting cereal rye as a cover crop in my garden. Since then the crop has germinated and made excellent progress toward establishing itself.
When rye seed germinates, it emerges out of the soil as a single shoot. As time goes by and temperatures are conducive to plant growth, leaves begin to form on the main shoot.
After a couple of weeks of growth, the plant enters the “tillering” stage of development.
Rye is a bunch grass, a self-descriptive term meaning that the plant grows in tuffs or bunches instead of spreading by over-the-ground stems called rhizomes. To spread and take advantage of growing space, the bunch grasses form extra stems called tillers. Tillers grow from the main stem of the plant.
When you look at a rye plants and see it staring to form dense tuffs, that growth you see is the tillers. Each tiller has the ability to form it own roots. In that way the plant has the ability spread vegetatively, essentially producing baby plants along side the main plant.
Farmers are concerned about encouraging tillering because the more fully-developed tillers the crop has, the greater the yield.
Extra tillering allows the plants to fill in bare areas thereby compensating for thin stands or weak germination.
My rye is is in the early stage of tillering and should be in fine shape going into the winter.