Tag Archives: weather

Greenhouse repair, stage 1

It has been four years since I built my greenhouse.  All in all, I am very happy with it.  This Spring we had some severe thunderstorms roll through (quite typical for central Oklahoma).  One of them dumped a lot of hail about the diameter of a quarter.  Many people in town got new roofs after the hail storm, but our new roof withstood the hail without any damage.  The greenhouse didn’t fair so well.

Roof of greenhouse riddled with holes from hail damage

The roof and walls of the greenhouse are made of triple wall polycarbonate.  There is one seam in the roof.  Based on my damage assessment I’m guessing that one of the sides of the polycarbonate must be tougher and more resistant to damage than the other side.  I had no idea when I installed the sheets.  Nor did I realize I was putting different sides up on the two pieces.  The repeated pounding of the hailstones punctured through the upper surface on one of the polycarbonate sheets and left the other sheet unharmed.  I wish I had known this when I was building the greenhouse.

The panel on the left is completely without blemish while the panel on the right has hundreds of holes.  You can also see where the panel has filled with water (top of the image).

At the time of damage I couldn’t just remove the sheet and replace it.  For one, replacement material is expensive and difficult to procure.  I had to buy a huge sheet (8′ x 36′) and cut it down to manageable sheets to get it home the first time around.  It was also still getting down near freezing some nights at the time, so I couldn’t leave the greenhouse unprotected.  Because I used triple wall polycarbonate the holes weren’t actually exposing the interior of the greenhouse to cold air from outside.  There was still a layer of protection.

Seeds from our Sycamore tree and other junk has been washed off the roof, right into the channels of the polycarbonate panel.

I stalled and life was busy and in the meantime, the holes of the roof allowed all sorts of water and junk to get inside.  Because the ends of the panel were sealed shut, the roof actually filled up with water, to the level of the lowest hole in each channel.

Water draining from one of the channels after I removed a screw attaching the panel to the frame.

What to do now?  Well, I have removed the damaged sheet, which was very heavy with the added weight of the water.  I drained the water and I am in the process of cleaning it out.  This is a time consuming process and I’m afraid the final outcome will not be a clear panel.  The walls and other roof panel of my greenhouse still look about as clear and clean as the day I installed them, but this roof panel will likely not be as pristine.

Typical hole punched by hail

Once the cleaning process is complete I will be patching the (hundreds of) holes with clear packing tape.  I have patched some areas and then tried to shoot water through those channels to flush out the junk.  That didn’t work as well as I had hoped, so I am going to try to use the holes to wash out the junk, and maybe also use a shop vac.

My patch job . Not the prettiest thing around, but hopefully it will do the job.

After the junk is out, I will do all of the patching, re-seal the ends of the panel, flip the panel so the repaired side is down, and then reattach it to the roof.  With the repaired side facing down any “leaks” would just be allowing the warm air from the greenhouse into the cell, rather than cold outside air into the cell.  Also, if it is true that the sides of the polycarbonate differ in strength then this puts the stronger side facing up to weather the next inevitable hail storm.

Stay tuned to see how the repair progresses.


Microburst = microplants

Over the last couple of years, our quiet little college town of Norman, Oklahoma has been hit with the full spectrum of natural (non-major) disasters.  Last year we had several wildfires that really scared some residents (who fortunately only lost trees, grass and a couple of fences).  We’ve had 3 tornadoes within city limits in the last 3 years (2 of them fatal).  We had an earthquake measuring somewhere between 4.3 and 5.1 on the Richter scale.  We’ve had flash flooding and three pretty substantial snowstorms, including one on Christmas Eve.  We had an ice storm that mangled all of our trees and knocked out electricity for most of Norman for a couple of days.

Angry mammatus clouds, just 30 minutes before the madness ensued.
Angry mammatus clouds, just 30 minutes before the madness ensued.

Lately it’s been really hot (>100F) and dry (actually kind of humid, but no precipitation).  Literally out of the blue, a storm formed just a county west of us last Tuesday (June 14) in the early evening.  It quickly turned into a beast and dumped some really heavy rain and hail on Norman.  When one of these storms creates a strong surge of precipitation and air towards the ground, it is called a downburst (or microburst).  When all of this momentum hits the ground, it spreads out, creating very strong horizontal winds.  In this case there were measured winds in excess of 70 miles per hour.  There are likely locations without wind gauges which had speeds around 90 mph.

Norman microburst
Norman microburst June 14, 2011. This is the best picture I captured with my iPhone during the event.

This microburst in Norman caused lots of houses to have shingle damage, downed fences, broken windows, battered trees and associated damage.  My sister’s chimney blew off their house.  Some people who don’t understand the physics behind this process claim there had to have been a tornado to cause the damage they see, but it was definitely a downburst.

Philodendron cordatum with holes punched in the leaves
Philodendron cordatum with holes punched in the leaves. Those are not natural fenestrations.

For the last couple of weeks my poor plants have been requesting a little drop of rain.  What they got instead was about 10 minutes of crazy wind and a pelting from marble to golf ball sized hail stones.   The more fortunate (top heavy) plants tipped over quickly and were laying on the ground in somewhat of a sheltered position.  The other plants really took a beating.  To give you an idea of the storm, watch this video.  Here’s another.  Since Norman is a town full of weather nerds, you can find plenty of videos and photos, if you search “Norman June 14 microburst”.

Another Philodendron with holes punched in the leaves.
Philodendron bipennifolium with holes punched in the leaves.

Many of my plants with “tougher” leaves are showing damage in the form of black or white bruises  where they were pelted with hail stones.  My Brassovola orchids which were sitting outside are showing white bruises, which I think is really interesting.  The pineapple plant is showing both black and white bruises.

Pineapple leaves with damage.
Pineapple leaves with damage.

Thankfully, I don’t think any of my plants are dead from this storm and my greenhouse survived without any noticeable signs of damage.  (Oh yeah, our house is okay, too.  But that’s really of less concern, right?)  Most of the plant damage is just a setback or cosmetic.  My plants which were sitting outside are not going to look nice for a while, but they’ll most likely all survive.  Probably the worst injury was an Aglaonema, which snapped along the stem.  But it was not the only stem of that species that I had, and the snapped stem will probably put out new growth shoots within a month.

Completely beat up Begonia.  This thing used to have quite a few leaves.
Completely beat up Beefsteak Begonia. This thing used to have quite a few leaves.

This Beefsteak Begonia got totally battered.  The good news is that it is one of 2 or 3 that I have and the others look pretty good.  Also, this plant grows super fast and gets pretty big.  I’m not all that worried about it, just showing it for illustration purposes.

Close calls with brutal weather

It has been untypically cold in Oklahoma over the last couple of weeks.  Oklahomans are used to some severe weather in all seasons – hot summers (sometimes humid, sometimes dry) with temperatures above 100 F, and cold winters with temperatures in the teens and snow and ice on the ground.  But it is pretty rare for us to get into the single digits or near zero.  I live in USDA hardiness zone 7a, which is a winter minimum temperature between 0 and 5 Fahrenheit.  However, it has been a good 6-8 years since we have dipped near 10F.  This year we have been hit pretty hard.

We have actually reached 0 F on two different nights over the last 2 weeks.  And we have gotten some real snow on the ground, in three different events!  Last week the all-time low temperature record for the state was broken when a temperature of -31 Fahrenheit was recorded in Nowata, Oklahoma.  At the same time, it was +16 Fahrenheit at the North Pole.  That’s just hard for me to believe.  The previous low was -27, set in Watts, Oklahoma in 1930.

My electric space heaters have done remarkably well keeping the temperature in the 60s in the greenhouse.  But the electric load has been trying for a single circuit.  Last week I woke up and checked the greenhouse temperature from the warm confines inside the house to find that it had dropped to 38 overnight in my greenhouse!  Prior to this my greenhouse had only gotten into the low 50s on one or two occasions.  I ran out to the greenhouse to find that the heaters were not on and would not respond to me hitting the power buttons.  The fuse had finally given out and the heaters had been off all night long, letting the temperature plummet (actually, it was more of a gradual decline) to a temperature that I can only imagine my plants didn’t like.

I found that having two space heaters plugged into the same outlet was not wise and since I didn’t have them plugged into a modern surge protector, they were drawing a higher load than the wiring could really  provide.  Thankfully our old screw-in fuse when out.  I replaced the fuse and plugged my main heater into a modern surge protected power strip, which will flip off when a large load is being drawn.  For the following nights, I ran an extension cord from another outlet out to the greenhouse to supply power to my extra heater.

It looks like I might have come through this debacle with only minor damage to some of my plants.  I don’t think I lost any plants outright, but some have lost leaves and will have to slowly recoup.

Winter weather and hardiness zones

We have received more than our normal share of winter precipitation this year.  I have spent my whole life in the same town, and I don’t really recall having more than 1 decent snow storm each winter.  This winter, we received a pretty good snowfall on Christmas Eve, measuring 8 inches in the middle of our front yard (away from any drifts).

Christmas Eve blizzard
Christmas Eve blizzard

Then we received an ice storm followed by 6 inches of snow last week.

Very thick icicle hanging from my greenhouse this week
Very thick icicle hanging from my greenhouse this week

In between those two snow storms our temperatures dipped down below 10 degrees Fahrenheit on three consecutive nights (6F, 6F, 8F).  We’re not really used to these temperatures, but I was thinking about our USDA hardiness zone.  I am located in zone 7a, which is rated for winter temperatures between 0 and 5 F.  This is one of those winters that makes our hardiness zone rating seem appropriate.  I would say that in the average winter, our minimum temperature is probably somewhere around 15 degrees F, but the USDA zones aren’t set up by average minimum temperatures.  You don’t want to plant a tree and expect it to survive in your zone only in the years that are above average.  You want it to survive 50 years or more.  So the USDA zones are set up by using long-term historical climatic minimum temperatures.

I discussed in a previous post how the hardiness zones only tell a small part of the story, but I would like to mention that again here.  The hardiness zones only tell you whether a plant can brave your winter minimum temperatures, not whether they will be happy with your amount of moisture or sunlight or long, hot summer days.  Some efforts have been made to construct other zone maps for variables like humidity and heat index.  Once these maps have been constructed and distributed to plant people, nurseries will need to start to label their plants, in order for them to be useful.  I know that there are a number of plants which can survive our winters, but would not like our heat waves when the temperatures can be above 100 degrees F for a week solid in the middle of the summer.

Hopefully these new maps will be circulated soon and start getting used.  It might seem like a lot of numbers to keep up with, but I can envision a 3 map system, where you just always remember you are a “7-5-8” or something like that.  If the order is kept the same (cold hardiness, heat index, humidity), it will make this new system user friendly and could help a lot of new gardeners.


Plant weather page debuts

You may or may not know that I am a meteorologist and software developer by trade.  Recently I decided to merge my occupational and recreational activities.  I have setup a new page here on the blog that shows the temperature and humidity (in the form of dewpoint temperature) of the environment in which my plants are growing.  You might have noticed the new link in the Pages section of the right panel –>.

(click for larger version)
(click for larger version)

The plot is called a meteogram, which means that it has meteorological data for a particular location, plotted on a time axis.  So you can see how certain variables (temperature and dewpoint, in this case) have varied over the last 24 hours (or however long the time axis spans).  Here is an example of a more detailed meteogram, produced by the Oklahoma Climatological Survey.

My meteogram is on the blog for a couple of different reasons:

  1. First and foremost, I think it’s cool.
  2. Other people can see what the temperature is like where my plants are growing.  You might think that you could just look that up on the internet, but you can’t.  My plants move in and out of doors, based on what time of year it is.  Also, I’m hoping to build a greenhouse one day, and the plants (and sensors) will be moving in there when it gets cooler outside.
  3. This will help me monitor the environment of my plants – even when I’m not at home.  [Not that there’s much I could do about it if I noticed that the temperature had plummeted and I was out of town.  But, hey, maybe I would call a family member and talk them into helping me out.]

The look of the meteogram is likely to change over the next couple of months.  I might add more sensors to my little weather station so that you can see how the temperature varies between the different locations where I have my plants – indoors, outdoors sun, outdoors shade.  Hey, maybe I’ll even get some fancy stuff, like an anemometer (wind gauge), and plot that data as well.

The plot will always be available on the “Plant Weather” page, and is currently being updated once each hour.

What do you think?