Posted: November 9, 2011

Even though it is cold outside and we are still thinking about what we should have gotten done in the yard this fall, let me remind you that in a few months you will be ordering seeds and wishing you had built that cold frame or greenhouse that has been on your to-do list for the past few years.

Start off by looking at the “Hobby Greenhouse Website”  I especially like their publications site.  They have an excellent magazine for members and a free download article about planning for your hobby greenhouse.  It asks questions like, do you want a living space or one for growing plants, and what kind of plants do you want to grow: orchids, vegetables, foliage, or the 100’s of other plants that hobbyist grows.

Greenhouses come in many forms.  The most common is the conventional even-span that looks like a small house with pitched roof and straight sidewalls usually built of glass or plastic.  Advantages of a detached greenhouse are that it can be placed so it receives sunlight; it’s also easy to add benches or expand later on.  However, because it is away from the house, utilities must be brought to it and costs will be higher than an attached or lean-to-greenhouse.

“Contrary to popular opinion,” says John Worley, Extension Engineer University of Georgia, “which holds that a greenhouse should receive unobstructed sunlight, it may be desirable to provide afternoon shade such as that given by nearby deciduous trees.  In winter, once the leaves have fallen, the greenhouse will receive the additional light needed at that time of year.  Be sure to take into account the possibility of falling limbs that can damage the greenhouse.”  For more info see (

An excellent home gardener reference is Greenhouses for Homeowners and Gardeners, NRAES-137 and is available for $30 from Natural Resources, Agriculture and Engineering Service (NREAS), 152 Riley-Robb Hall, Ithaca NY 14853-5701.

Greenhouse construction plans are available on the Internet from Cooperative Extension


Mulching and Protecting Tender Perennials

My father gave me the advice that perennials should be mulched and protected in late November around Thanksgiving.  His rational was that plants will be dormant and the rodents will have other found other winter homes rather than your nice fresh mulch.

The technical reason for mulching is to keep perennial plant roots COLD!  Horticulturist recommends mulching when the soil temperature reaches 25 °F and the plants are fully dormant.  About three inches of mulch is just about right to prevent alternate freezing and thawing.  With bark put down 3-4 inches so it will compact to that magical three inches depth.  With straw or leaves you will need 6-8 inches, as it will compact much more.  Shallow rooted perennials like mums, roses, azaleas, and those that were recently planted will need to be mulched.

The second reason for mulching is to prevent frost heaving.  This often occurs in clay or slightly wet soils during winter freeze and thaw cycles.  The most common plant subject to frost heaving is strawberry.  The third reason is to prevent soil erosion.

Live Christmas Trees

I am an advocate of using live (balled and burlaped or potted) Christmas trees as the focal point of your holiday decorations.  I hate to see a tree cut down and then burned or composted, when just a little extra effort you can buy a truly living tree, roots and all.  The kids will remember it and so will the parents when you plant it.  Just to remember to dig the hole early and cover or protect soil so you replant it in the yard if ground is frozen.  Years latter you will point to that tree and say something like, “Remember when the kids were small and we planted that beautiful Christmas tree, see how big it has grown.”

Buy a healthy tree from your nurseryman or garden center, most will not guarantee the plants, but my experience is that you will have about a 75% success rate:

-Gradually introduce your live tree to home conditions by first conditioning it by bringing it into a garage or porch for 3 days, keeping it SLIGHTLY moist, but not wet or soggy.

-Spray with an anti-desiccant or anti-wilt (Wiltpruf or Vapor Guard) product to help it survive indoors, available when you buy the tree.

-Locate tree in a room away from heat or sunlight, use a large galvanized tub to hold the roots.

-Stabilize with bricks and water sparingly, plant in 7-1 days outdoors.

Alan Michael is the Penn State Cooperative Extension Educator for Commercial Ornamental Horticulture serving the Southeast Region.  Penn State is committed to affirmative action, equal opportunity, and the diversity of its workforce.  Penn State Extension in Cumberland County is located at 310 Allen Road, Suite 601, Carlisle, PA   17013, phone 717-240-6500 or email