The sunny, spring-like weather makes the greenhouse the place to be.   That southern exposure could heat the inside of the greenhouse up to well above 90 degrees, making it bikini weather if we chose to do so.  But of course we are growing plants in the greenhouse so we start venting it out to cool it down to a moderate temperature of 75 or so.  Once that sun goes down the temps in the greenhouse also go down very quickly. Without supplemental heat the greenhouse temps would plummit to below freezing.

In the previous years I was always very anxious to get planting into the greenhouse.  I recall the first two years living in MN I was planting peppers and tomatoes as early as mid-February.  I guess my early days of greenhouse planting were guided by the fact that most of the professional greenhouses in the state of MN were selling 6inch and foot high plants by early May.   The problems with planting that early were many.  First, the early planting meant that the heater in the greenhouse was working overtime for a month more than needed.  Second, all of the plants needed much more work because they would have to be "potted on" to larger pots before they went into the ground (this also meant they took up much more valuable greenhouse space in the month of May).    The plants that were planted later were actually stronger, and less vulnerable since they weren't pampered so much in the greenhouse, and their root mass would not have to be disturbed as much as the larger plants. Finally, there ended up to be not much of an earlier harvest of the crop in the end.  So the returns on the expense were none.

Every year since we started we have pushed our first greenhouse planting dates later and later until we usually are not kicking on the heater in the greenhouse until mid-March.  This year we may get ahead of the schedule a little bit because the forecast is looking very mild for the entire month of March.  I will start our leeks and onions by seed next week. 

 For onions, leeks, scallions (all in the allium family) we use a method called, "multi-planting."   Multi-planting means simply that we place 3-4 onion seeds per cell in the greenhouse flat.   On our home page you will see a picture of a greenhouse flat with holes pushed into the potting mix within the cells.  One of these flats has 72 cells and each of these cells will receive 3-4 onion seeds.  When we eventually plant the onions we will plant the cells one foot a part from each other allowing them room and enough nutrients to grow properly.  Normally, if you were to plant each plant individually you would need approximately 4 inches of space between plants.

So, here's a simple math question for you:

We grow 3 main varieties of onions,  Walla Walla, Mars (red storage), and Eagle (yellow storage) and Leeks.    We will plant 44 flats of each variety. All of these will be planted on the same date.  Each seed should produce one onion.  How many total onions will we harvest in a year if all the onions grow properly?  Remember, we grow in a 72 cell flat and each cell receives 3-4 onions.

 In addition, we grow scallions(these are multi-planted with 12 seeds/cell).  We have 4 different plantings of scallions, and we plant 11 flats for each planting.  How many scallions will we harvest?

You can email me the answer. It will be interesting for me to see how many people are actually reading my blog. (no calculators--let your brain do a little work) Also, this may be a fun activitity for your kids to work on and realize how important that math is in real life. 

Gary