Bloom Day from the Greenhouse

A friend told me today that one of the things she liked about greenhouses was their quiet energy.  My greenhouse quiets my soul.  It makes me feel serene and helps to eliminate the stresses of my day for a little while.  There's so much beauty to be found and today I'd like to share some with you.

Mother of Millions is a common plant that is easy to share with others.  Many baby plants are born on the leaves of the mother plant, and when they fall to the ground each one sprouts into a new plant.  This plant was shared with me in this way.  I was given multiple babies and they grew and grew until finally this winter they flowered.  It was quite unexpected, and because it was unexpected, it was all the more special.

In a heated greenhouse environment, hibiscus never stop blooming, but it doesn't make them any less beautiful.

Propagated from a cutting during my Master Gardener class in October 2011, Country Girl mum is about as cheerful as they come.  My little cutting has grown up and is already blooming.  They grow up so fast.  Sigh...

Bougainvillea are rather ubiquitous here is Texas, but there are probably not many blooming in February like this specimen.

I bought this abutilon from Barton Springs Nursery where they used to have a magnificent specimen growing in a moist, shady spot.  I think it died last winter during the 17 degree cold snap.  You normally can grow these in the ground, but I've never been able to keep mine watered enough, so I've been growing this one in a pot.

During an upper east side garden tour, some generous home owner gave me my first angel wing begonia cutting.  I carried it around all day in a diet coke can till I could get home and plant it.  Today, I have many of these easy to propagate plants, which I share with anyone who asks. 

This desert rose, adenium obesum, has not stopped flowering all winter.  It really likes life in the greenhouse.

Globe mallow is not a greenhouse plant, but this guy has been living the high life in the greenhouse for months. I'm going to plant it outside in the garden soon.  I've heard these plants are reliable bloomers that will continue to bloom during a mild winter.

The wonderful smell of this Meyer's lemon in bloom promises many juicy, sweet lemons to come.

While neither of the next two plants are blooming, I just had to share them.  The first is a new addition to my collection called a paper spine cactus.  The spines are not sharp and this plant is just too cool!

My final plant is one of my all time favorites.  This is Persian Shield.  Technically not in bloom, this plant can put a lot of blooms to shame.  Grown in the shade, this plant really pops.

I hope you enjoyed these beautiful flowers from my greenhouse.

Happy Bloom Day!  Please visit May Dreams for more great Bloom Day blogs.

Passive Solar and Other Hot Topics

Heating a greenhouse in the winter can be expensive.  I’m all for saving money, so I have been searching for ways to make heating my greenhouse more efficient.  This search has led me to consider using passive solar energy as well as insulation to help keep my greenhouse warm.

So, what is passive solar?  Passive solar is a method for collecting and using the suns energy without the use of a mechanical device.  Intriguing, right?

By following some basic greenhouse design principles, I started using passive solar techniques without even realizing it.  My greenhouse is located in full sun with the largest part of the roof facing south.  This allows my greenhouse to efficiently capture the suns energy.  On December 6^th, when the outside temperature was 50 degrees, it was 81 degrees in my greenhouse.  The suns energy was doing all the work to keep the inside of the greenhouse toasty warm.

Greenhouse South Facing Roof

Capturing the suns energy and hanging on to it are 2 different things.  When the sun goes down, a greenhouse does not have any special properties that will allow it stay warmer than the outside.  Without a source of heat, a greenhouse will freeze if the outside temperatures are freezing.

Storing the suns energy requires something referred to as thermal mass.  The thermal mass, usually water, stone, brick or concrete, heat up during the day, and then, at night release the stored heat.  Water is the best source of thermal mass, so I installed two 55 gallon barrels filled with water in my greenhouse.  A 55 gallon barrel takes up a lot of space, so in a smaller application, you might try wine bottles filled with water like Jenny at Rock Rose.

To make the best use of my 55 gallon barrels I’ve placed them on the north wall where the southern sun will hit them directly through the roof.  My 55 gallon barrels are doing double duty as heat collectors and supports for a plant table.

55 Gallon Barrel

Plant Table Supported by Barrels

What kind of return will I get on my 55 gallon barrels?  Well, a gallon of water weighs 8.3 pounds, so a 55 gallon drum contains 456.5 pounds of water.  When the sun goes down and the temperatures start to fall, each gallon of water will release 1 BTU per degree of temperature dropped. So, let’s say the water made it up to 80 degrees and the temperatures are going to drop down to 50 degrees.  That’s a 30 degree temperature drop, or 30 X 456.5 pounds, which comes to 13,695 BTUs. 

To put this perspective, my 1500 watt electric heater puts out about 5,120 BTUs per hour.  To fully heat my greenhouse with water barrels, I would need a lot more water barrels, but hey, it’s a start, right?

If you want to take this a step further, check out this heat calculator from ACF Greenhouses (http://www.littlegreenhouse.com/heat-calc.shtml).  This calculator will help determine how many BTU’s you will need to maintain your greenhouse temperature at your desired level. 

In order to hang on to the heat being generated by either passive solar or mechanical heaters, it’s important to seal up air leaks and insulate when possible.  I added 6 mil plastic sheeting to the north wall, plus I sealed up the air intakes and fan shutters, which I won’t be using during the coldest part of the winter.  It’s important not to cut off all ventilation, so I will leave 3 of the automatic vent openers active on the clerestory windows (see previous post). 

Sealed Air Intake Vent

Sealed Exterior Fan Shutter

I have read that bubble wrap makes an excellent insulator, so my goal is to eventually insulate the north wall and north roof with bubble wrap.  Greenhouse supply stores sell special UV protected bubble wrap for this purpose.  Regular bubble wrap can also be used and is readily available at office supply stores, or better yet, get recycled bubble wrap if you can find it.

Another place to add insulation is the foundation.  Cold air can seep into the greenhouse from the surrounding soil.  I have temporarily packed the foundation with a hay, but my long-range plan is to install a foam insulation barrier.

Hay Foundation Insulation

Example of Foam Perimeter Insulation

Will all these measures help me save money?  I sure hope so.  I've already noticed that the greenhouse heaters have an easier time maintaining temperatures when it's freezing at night.  That's good news for my plants and my pocketbook.

Zap! Hard Freeze

The first freeze of the year, and mother nature hit hard.  Looks like we bottomed out at about 26 degrees.  Ouch!  I wasn't expecting that, and I didn't cover anything.  
 
In the veggie garden, cabbage and rutabaga weren't phased at all.  The broccoli looks a little unhappy, but it will bounce back.  The 'Bright Lights' Swiss Chard did not fair well.  This variety of chard does not tolerant freezes as well as some of the others.

The remaining pepper and tomato plants are history.

 
On the ornamental side of the garden, the Root Beer Plant, which was lively just yesterday, is looking like a wet dish rag. 

 
This spider lily looks a little defeated, but not totally down for the count.

 
Purple Lantana was one of the stars of my drought stricken garden this year.  The freeze nipped the leaves, but some flowers are hanging in there. 

This purple vitex (vitex trifolia atropurpurea) is evergreen in zone 10.  In zone 8, however, it will eventually die back to the ground and return in the spring.

 
In the greenhouse, a little extra help from a portable propane heater kept everything a toasty 52 degrees.

 
Despite the chilly start, the inside of the greenhouse maxed out at 81 degrees.  Balmy to say the least.  
 
Flowering plants such as this begonia are still blooming. 

 
This desert rose has decided to bloom too.

This night-blooming cereus is enjoying it's hanging basket in the sun.  The pink fruit looks very similar to a prickly pear and is just as edible.  Unlike the prickly pear, the cereus fruit is spineless.

Another freeze is on the way for tonight.  Bundle up.

Greenhouse Update - Heating for the Winter

In Texas, we are blessed with short, reasonably warm winters.  Still, cold fronts do come, and temperatures can drop unexpectedly.  Last year’s 17 degree low was one of those little unexpected happenings that most of us probably hope will not be repeated this winter.

It’s hard to imagine cold weather will eventually arrive, when my greenhouse hit 96 degrees today.  The bottom line is that Texas temperatures can get crazy, so it’s important to be prepared with an adequate greenhouse heater.  My ideal heating system is a little beyond my budget at the moment, so this winter I am improvising.

There are 3 things that I consider necessary for heating my greenhouse; a thermostat, a greenhouse heater, and a backup heater. 

My greenhouse is 320 square feet with a high ceiling.  Calculations show that to keep the greenhouse warm under the worst conditions, I need a heater rated at about 23,000 BTU.  I can’t get that much power from a 110v heater.  So, until I can afford a 220v electric line and a super powered heater or two, I’ll be running 2 - 110v heaters and hoping for a mild winter. 

The 2 primary heaters I selected are economical, electric utility heaters designed for use in a greenhouse or workshop.  The heaters will be stationed at opposite ends of the greenhouse pointing inward towards the center.

Each heater will be operated from a separate thermostat.  The thermostat will be set at 45-50 degrees and will automatically turn the heater off and on as necessary. 

In case of an electric outage, I have purchased a propane heater to keep on standby.  This heater attaches to a standard size propane tank and will run about 27 hours on 1 tank.

I can currently view temperature conditions in my greenhouse from a weather station readout in my house.  The weather station sensor, which is located in the greenhouse, shows the current temperature and records the daily minimum and maximum temperatures.  

A weather station is very handy, but the item on my wish list is a greenhouse freeze alarm.  The alarm would alert me in case the heaters stopped working and temperatures dipped into the danger zone.  I hope to have one of these little gems before the really cold temperatures arrive.

Greenhouse Build - Week Four

The greenhouse house project is complete.  Can I hear an AMEN!

I'm ready to move in the plants, but before I do, please join me for a tour.

The double french doors are both operable providing an extra wide opening for bringing plants in from the cold.

The clerestory windows using Gigavent automatic solar vent openers allow heat build up to be released from the roof peak.  Solar vent openers work without electricity.  The vent openers contain a mineral that expands when heated.  The expansion pushes a piston that slowly opens the window.  When the mineral cools, the piston slowly lowers the window back to closing.

Sliding windows open along the front and back walls for cross ventilation.

The exhaust fan will blow out hot air from the greenhouse, while pulling cooler air in through the motorized shutters.

Exhaust Fan

Motorized Shutter

Shutter Vents Exterior View

 The finished interior space is 16 feet wide by 24 feet long with a 14 foot ceiling.  The high ceiling will provide plenty of head space for potted trees and hanging baskets.

Night Blooming Cereus and Zig Zag Cactus
Hangs From the Rafters

Well, that's the end of the tour.  Now, let's swing those doors wide open.  The long awaited moving day is about to begin.  Time to move plants into the new greenhouse.

Greenhouse Build - Week Three

When has a construction project ever proceeded on time and on budget?  The answer to that elusive question, eludes me.  Progress has been made none the less, but the greenhouse is not finished. 

More on that, but first, an unexpected freeze warning sent me scrambling on November 3rd. Plants were moved to the front porch and into the house to protect them just in case.  

Tender Plants Staged on Front Porch

Covered Plants Hope for the Best



Welcome to the Indoor Jungle.  



Back to the construction update...
    
Greenhouse construction has been proceeding, but the devil's in the details, and those details have really slowed things down.  The trim work and finishes are taking more time than anticipated.  Still, some exciting progress was made.  In the picture below, the automatic solar vent openers can be seen opening the windows.  The vent openers getting the most sun open fully, while those in the shadows lag behind.

A view from the front shows the window trim is almost complete and decorative corbels are being added to the clerestory roof line.

A view from the back shows the 6 foot slider windows trimmed out.  The clear polycarbonate, while see through, does not provide the same clarity as glass.  These windows will provide a nice view as well as cross-ventilation.

With any luck, the next update will be my final progress report.  Cross your fingers, say a prayer, knock on wood, and stay tuned.