Friday, February 18, 2011

Starting the seeds, or, Better late than never

OK it’s time to get some seeds in some pots, but first a little of last year’s business.  With the warmup the parsnip was showing a some green new growth on the tops.  The ground is no longer frozen so I dug the remaining parsnip up, along with one rutabaga.  There’s still some rutabagas left in the bed and I probably won’t use them all, just planted too many and don’t like them that much, except in beef stew.  Parsnips are another story - these are very sweet.  

I finally made space in the sunroom to set up a seed-starting workstation.  It’s pretty basic – a table, fluorescent light fixture hung from ceiling hooks, side reflectors, heat mat, rheostat, and light timer.  The light fixture is a 4 foot work light with a wide reflector that holds two 32 watt T-8 bulbs, from Lowe's.  I made the side reflectors by attaching L-angle to white prefinished 4' shelves.  The reflectors bounce light so it comes from the sides as well as the top, resulting in fuller plants.   Even with the reflectors, this setup gives just adequate light for seedlings, but if they are not planted too close will not get spindly.   I wasn't willing to spend the money on a thermostat control for the heat mat, they're a bit pricey.  Instead I plug the heat mat into a rheostat, insert a temperature probe from a digital thermometer into the potting soil in one of the pots to monitor the soil temperature, then adjust the rheostat to get the soil to the desired temperature, usually 75 to 85 degrees. 

I only use the heat mat when trying to germinate seeds, and will move seedlings already growing to a separate flat off the heat mat.  I’ve found that the arrangement of lights and reflectors will maintain a temperature of 55-70 degrees inside the lighted space with no additional heat source (the unheated sunroom is usually about 50-60 degrees this time of year).  This temperature is fine for cool season crops.  This picture shows the light fixture with the reflectors, heat mat, temperature probe and rheostat.

In the past I put the pots into flats and added enough water every day or two to wet the soil at the top of the pots, which requires a lot of monitoring.  You don’t want a standing water in the flat as this will drown the seedlings and invite disease, or at least mold and algae growth, and you can’t let the soil dry out.  There are systems that float a styrofoam sheet with growing cells on a reservoir of water.  I don't like the expandable plugs though and found that cheap plastic pots and multicell trays provide the most flexibility to raise different size plants. This year I tried to design a system that should need less attention using a capillary mat to wick water from a bottom flat.  The pots are set in a perforated flat that is held above the water reservoir by spacers.  Two slits are cut at each end of the flat and the ends of a capillary mat are pushed through the slits and sit in the water reservoir of the lower flat.
Putting this together is very straightforward, requiring a cordless drill, some spacers and screws.  For spacers I cut three 9” pieces of ¾ inch PVC conduit which I had on hand and screwed them to the bottom of the flat at the ends and the center.  The pipe strengthens the flat, which is very flimsy especially after the slits are cut, and also holds the flat above the reservoir.  I used some white hex head screws with a self-tapping point that were left over from an earlier project.  The flat had to be turned on its side while I used a cordless drill in one hand to drive the hexhead screw into the conduit, held with my other hand.  The hexhead screws are much easier to use in a cordless screwdriver.  The bits are available at any hardware store.  This is a top view of the perforated flat with a few extra screws tossed in to show what they look like.  Note the wide head on the screws. 

And here's a bottom view showing the PVC spacers:

The picture below shows the flat upright with the slits cut at each end. These perforated flats are very flimsy and the slit is easily cut with a sharp knife.  The capillary mat is trimmed as needed with scissors and the ends are then pushed through the slits. 

The bottom picture shows the assembly from the side with the ends of the mat hanging beneath the flat. The entire assembly is set into a solid flat so the ends of the mat lay in the lower flat.  Water is added into the top flat until it wets the mat.

That's it for now.  I'll update the success, or not, of this system in the near future.

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