Monitor soil temperatures before planting

Soil temperatures have been cool enough during April that it has slowed down plant growth. My winter rye cover crop looks to be a week behind last year at this date and last year was later than normal as well. So that means we’re really behind. The apple tree buds have finally, slowly opened.

This may be the year to monitor soil temperatures more closely than usual if this cooling trend continues.

Some vegetable crop seeds can be sown into cold soil and do quite well under those conditions while others will not germinate or grow at all. There are certain minimum temperatures that seeds need in order to germinate. Seeds languishing in cold soil will be damaged or more likely, rot in place before they sprout.

For example, at 35 F you can expect spinach, onions, parsnips and lettuce to germinate. We’re well past that point by now.

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Although not as durable, a kitchen thermometer makes an adequate replacement for a soil thermometer

Beets, cabbage, cauliflower, Swiss chard, radishes, turnips, peas, and broccoli will all germinate at 40 F. Even though they are not technically seeds, seed potatoes will begin to grow at that temperature too.

Sweet corn requires the soil temperature to be at least 50 F. If they are pinched for time, some farmers will plant corn at lower soil temperatures but they always use seeds treated with fungicide to keep them from rotting in the soil.

A minimum soil temperature of 60 F is needed for warm weather crops like beans, cucumbers,melons,pumpkins and squash seeds to sprout.

Keep in mind that these are minimum required temperatures. Optimum germination temperatures may be five, ten or even twenty degrees higher in some cases.

You may have noticed that I didn’t include many common vegetables like peppers or tomatoes in these lists. That’s because in our growing area, those plants are generally grown as started transplants, not from seeds planted directly into the ground.

Bob

Soil temperatures

Soil temperatures have been cool enough during April that it has slowed down plant growth. My winter rye cover crop looks to be a week behind last year at this date and last year was later than normal as well. So that means we’re really behind. The apple tree buds have finally, slowly opened.

This may be the year to monitor soil temperatures more closely than usual if this cooling trend continues.

Some vegetable crop seeds can be sown into cold soil and do quite well under those conditions while others will not germinate or grow at all. There are certain minimum temperatures that seeds need in order to germinate. Seeds languishing in cold soil will be damaged or more likely, rot in place before they sprout.

For example, at 35 F you can expect spinach, onions, parsnips and lettuce to germinate. We’re well past that point by now.

.
Although not as durable, a kitchen thermometer makes an adequate replacement for a soil thermometer

Beets, cabbage, cauliflower, swiss chard, radishes, turnips, peas, and broccoli will all germinate at 40 F. Even though they are not technically seeds, seed potatoes will begin to grow at that temperature too.

Sweet corn requires the soil temperature to be at least 50 F. If they are pinched for time, some farmers will plant corn at lower soil temperatures but they always use seeds treated with fungicide to keep them from rotting in the soil.

A minimum soil temperature of 60 F is needed for warm weather crops like beans, cucumbers,melons,pumpkins and squash seeds to sprout.

Keep in mind that these are minimum required temperatures. Optimum germination temperatures may be five, ten or even twenty degrees higher in some cases.

You may have noticed that I didn’t include many common vegetables like peppers or tomatoes in these lists. That’s because in our growing area, those plants are generally grown as started transplants, not from seeds planted directly into the ground.

Bob

Protecting bonsai from bitter cold

There’s some talk among weather prognosticators about a speed bump developing in the polar vortex this winter. Some are saying very cold, below normal temperatures are just over the horizon and heading our way. If you haven’t already done so, now’s the time to finish up prepping your garden for winter.

I’ve done all I can for my gardens making sure they are all set for the cold weather . The last item I had on my outdoor things-to-do list was winterizing my bonsai trees. Usually I have them all tucked in around the first week of December but this year it’s been so mild that I left them out until this week.

Every year I change the way I winterize them but there are a couple of important things I always make sure happens. First, the roots and tops are protected from the extreme cold and fluctuations in temperature. I do that by digging an over-sized  hole in a protected area big enough to bury my pots.

The second thing is to make sure melt water doesn’t settle in to the pots. Re-freezing of water in the pots can cause them to break due to the expansion that occurs when water freezes. So, I tip the pots on their sides keeping the water out.

Placing them on their sides also allows part of the top branches to be in the hole. The surrounding soil helps moderate the temperatures that they are exposed to.

This year I dug my hole in a well-drained area near a group of white pine trees. The trees will slow down brisk winter winds lessening the chance of desiccation. After placing the trees in the hole I covered them with a layer of white pine needles. That will help insulate them and make it easier to clean off the soil when I take them out in the spring. Then I took the soil that was left from digging the hole and covered the needle covered plants.  I also banked up the soil on the pot end of the hole giving additional protection to the roots.

Here’s what they look like with a layer of needles and soil. Next comes a layer of leaves.

Finally, I hauled in tree leaves and covered the entire area including the plants. A small amount of branches are still peeking up through the leaves. Later, when the Christmas tree comes down I’ll cut off boughs from it and lay them over the mound. The boughs will help catch snow allowing it to drift over the spot and provide even more insulation.

I know this sounds like a lot of work for a few plants but my bonsai are valuable to me. I’ve been caring for one tree for seventeen years so I sure don’t want to lose it now.

Bob

Digging dahlia tubers late

Last week I talked about my potatoes that I dug up very late in the season. What I didn’t mention was that same day I also dug my dahlia tubers that were still in the ground. Turns out they where in fine shape shape as well.

It makes perfect sense that the tubers would look so nice.  The ideal storage temperature for dahlias is around forty degrees Fahrenheit and that’s about what the soil temperature was. I checked the soil temperature in my garden again this morning and found that even now, during the first week of December, it’s running about 40F.

What kind of surprised me was how warm the soil is even with the colder than normal November we experienced. Looking back on the several weeks,  a pretty good set of circumstances lined up for my dahlias. First, the tops were froze back by the frost back i October. Then I left them in the ground for well over a month. That allowed the tubers to develop healthy “eyes”, just like the eyes on a potato. With strong eyes, my tubers should make good, strong growth next spring — that is if I take good care of them over winter.

This is a typical dahlia tuber but they come in a wide variety of shapes and sizes.

There’s a few simple tricks to keeping dahlias over winter. The first is to store them at the proper temperature and we already know what that is — just don’t let them freeze.

The second crucial factor is humidity. If left out in the air during storage, the tubers will dry out due to the low humidity we typically have in our homes in the winter heating season. So the solution is to store them in air tight containers. For a small amount of tubers, maybe under a hundred or so, I find keeping them in zip-loc bags is a good way to go. I usually separate the clumps of tubers into singles, then place one or two in each bag. To maintain good humidity I add moist sawdust to the bag. If you have more that one tuber per bag, the sawdust also keeps the tubers from touching each other. While you’re at it, add a tag so you know what variety it is.

Even though I had success in the past using peat moss, potting mix or garden soil, I’ve found that sawdust works best for me. I’ve heard of people using shredded newspaper but have never tried it. However, with so many people opting to get their news online, printed newspaper is getting harder and harder to find these days . You can easily solve that dilemma by subscribing to Detroit News home-delivery, but I digress.

The third and final secrete is to check on them once in a while. Open them up and make sure the packing material is still moist. Also, toss any rotting tubers you might find. It’s pretty disappointing to open them up in the spring only to find out your tubers were ruined due to neglect over winter.

Those plants you bought from the garden center and planted in your garden, most likely grew a set of usable tubers. Since soil temperatures are still hovering around 40 degrees F, it may be fun to check in your garden to see if your dahlia tubers are still good. Dahlia farms are asking $3.00 and up for each tuber (not including shipping) so it may be worth your while to poke around in the garden. Let us know in the comment section what you find.

Bob

Two weeks behind at the end of April

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.

Compared to last year, the rye cover crop is way behind schedule.
Last year’s rye crop was over a foot tall on the same date.

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.

Bob

One local interpretation of Groundhog Day

Growing up in a rural area of Monroe County Michigan, I had a chance to absorb a lot of our local farm culture. Back them there were plenty of old-timers who, in their younger days,  had farmed their acreage with teams of horses. Those gray-haired farmers had plenty of advice and time-worn proverbs to pass along. One that stands out for me is the meaning of Groundhog Day.

I don’t know the history of  Groundhog Day in Punxsutawney but the town has so successfully managed to turn Groundhog Day into its own event that many people don’t even know, or care, that this minor holiday has been around way before weatherman Phil Connors got caught in that time-loop in Pennsylvania. The first time I ever heard of the town of Punxsutawney was on an episode of  The Rocky and Bullwinkle Show. I’m not sure in what context it was, I just thought it was funny to hear a cartoon character say “Punxsuatawney Pennsylvania”.

Most of the farmers in our area had some sort of livestock, often it was dairy cows. They would grow corn and hay as feed for their animals rather than purchase it off site from somewhere else. That meant storing feed on the farm; dried corn, still on the cobs, in corn-cribs and hay up in the second story hay mows above the livestock area on the ground floor. Farmers could easily judge by eye how much their livestock were eating.

Feeding livestock through the winter could be a challenge if the previous growing season’s harvest was below normal. Groundhog Day was, according to those farmers I knew, the half-way point of winter. By that they meant, if you still had half of your feed or more left in storage by Groundhog Day, you will make it through to spring. If not, then potentially you would run short of feed.

In our rural elementary school, Groundhogs Day was a fairly big deal. Our teachers never mentioned the practical side of the day but we did learn about the whole six weeks before spring thing. My classmates would come in to school on the morning of February second and excitedly report if they thought there was enough sunlight for a groundhog to cast a shadow.

I still use this day as reminder when I look in my deep-freezer and estimate how much frozen garden produce I have left from last year’s harvest.

Bob

Use warm temperatures during January thaw to control insects with water

 

During many winters we have a January thaw. We had a very welcomed warm spell last week and it looks like there will be another warm-up this week too, even though it may not be quite as warm this time around.

I always like to take advantage of those warm mid-winter days to freshen up my house plants and others that I have growing  inside.

Three of my citrus trees, which are about six feet tall including the pot, share space in a southern window in my woodworking area. That means their leaves are often covered in fine sawdust depending on the project I’m working on. I recently finished a project that required quite a bit of sanding which developed a lot of sawdust that settled on the citrus tree leaves.

Last week’s thaw gave me the opportunity to haul out my two wheel hand-truck and wheel out the heavy potted trees out to the driveway. I didn’t need to hose off the plants because of the drenching rain that came later in the day. That rain was all that was needed to get them clean. Since then however, I’ve generated more saw dust and they’re all dusty again.

The good news is that temperatures are predicted to be near 50 degrees F during the next couple of days. That’ll be the the perfect time to wheel them back out and rinse them off again, only this time I’ll have to drag out the hose. Some of my larger house plants are going to get a good outdoor rinsing too.

I rinse my citrus trees every year we have a January thaw. My trees are 17 years old.

This mid-winter rinsing not only washes off dust but even more importantly, it removes many of the small insect and other pests found on indoor plants such as spider mites, mealy bugs and scale. The population of  those types of pests can build up to a damaging level inside a warm, dry winter environment like we have in many Michigan homes this time of year. Rinsing with water knocks back the insect population to a tolerable level.

Mature citrus tree leaves are tough and can handle strong streams of water. Other plants though have more tender leaves which can be bruised by a too vigorous spray from an exuberant gardener — I know, I’ve done it.

If you plan to do a mid-winter rinsing, I suggest you start with a fine spray and increase the pressure if needed.  You’ll have to use your best judgement as you go along. I use a three-hole nozzle that puts out a very fine, yet strong stream of water that knocks off just about everything without damaging leaves. Be sure to spray the under-side of the leaves. That’s where the biggest concentration of pests will be hiding.

Bob

 

 

 

 

 

 

 

Fall planted plants are off to a good start this year

Now that normal winter weather is here, it’s easy to forget about the mild fall and early winter we had. That mild autumn and early-winter will probably turn out to be a real bonus for gardeners especially for those who did any kind of fall planting.

The roots of most fall planted plants continue to grow as long as the soil is not deeply frozen. A long, moderate fall and early winter like the one we had this past season, was ideal for fall root growth. That means the plants are now well established and will be raring to go this spring.

Garlic is one crop that is normally planted in the fall. I’m going to predict that this year your garlic crop will be better than normal. We should see larger than normal bulbs with larger and more cloves per bulb at harvest time. That’s assuming all other factors such as weed control, fertilizer and soil moisture are the same as usual.

Our tulips, daffodils, hyacinths and crocus should produce great flowers this spring too.

The same hold true for trees and shrubs. Any woody plants planted this past fall should be in great shape to make excellent growth in the spring. Anyone who planted fruit trees this fall will have effectively  gained nearly an entire growing season — as far as root growth goes.

If we have one of those springs where we quickly jump from winter right into hot weather (which sometimes happen around here) those fall planted tress will be able to shrug off the stress. On the other hand, spring planted trees under hot, dry conditions will not fare as well.

Keep in mind that spring is still the best time of the year to plant tree and shrubs. This year however,  el nino helped us out by allowing a moderate fall and early winter.

The US Department of Agriculture has developed digital tools that farmers can use to track developments like those of el nino and others, allowing farmers to make better planting, harvesting, storage and marketing decisions. As gardeners we can piggy back on that research and apply it in our own little corner of the world.

I plan to make a note in my garden journal to keep an eye for the next developing el nino and plan accordingly.

Bob

Too much rain causes waterlogged garden soil

Gardeners in our area are having to deal with unusual amounts of water in their gardens. The amount of water in the soil is more like what we would see in early spring after the snow melt rather than late June or early July.

Driving around I see standing water all over our area with no place to go. Soils in many places are waterlogged which means big trouble for plants.

Most plants are able to cope with a day or two of flooding but after that, complications start to set in. The biggest problem is a lack of oxygen in the soil. Plant roots need oxygen to function.

All types of soil contain air spaces between soil particles. Fine textured soils with a lot of clay, have very small air spaces while sandy soils have large air spaces. This is very important because plant roots need access to soil air, they can’t efficiently use the oxygen dissolved in water.  When we have too much rain, these air spaces fill with water. Once that happens, the plant roots begin to drown and eventually die.

A water damaged plant, curiously enough, shows symptoms exactly like a plant that has been growing in a drought. In the case of a drought, there is not enough water for the roots to absorb so the upper part of the plant wilts. With a waterlogged plant, the upper part of the plant also wilts because can’t the roots have stopped working so no water gets moved into the upper parts of the plant.

After a the soil returns to normal, plants need to be watered more often because they have fewer roots. Often, if the damage is not too bad, the plant will recover by growing more roots to replace the ones lost by drowning. If it the damage is too great, the plant will be stunted and never be able to live up to its potential.

Raised beds are helpful in low lying areas.
Raised beds are helpful in low lying areas.

Another problem, especially with a vegetable garden, is the potential for contamination. In urban or suburban neighborhoods where all sorts of properties are nearby, there is the potential for flood waters to carry contaminants like bacteria or chemicals. Think of that dog kennel down the street or that parking lot with runoff water carrying motor oil and other debris.

You may want to think twice about eating vegetables exposed to contaminated flood water.

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.