Fall planting... calibrating the seeder

I'm finishing up the planting of various things in the field; I'm plating two different pasture mixes, some alfalfa, per the local agricultural college's recommendation and some clover. 

Grass seed is expensive; about $2/lb, and alfalfa seed is even more so; $3.75-$4.50 a lb, in 50lb quantities.  a 50 pound sack of alalfa seed is $200!

The seeding rates, the amount of seed that you put down per acre, is between 15 and 20lbs of seeds, and it varies a little based on what you're planting, and to do a proper job I basically decided that I needed a seeder. 

Calibrating the seeder with a tarp

I found a used brillion 1201 sure-stand seeder that is basically two seed boxes (one for very small seeds, and the other for small seeds), with two compactor wheels below.  As the wheels turn they turn a gear that moves an agitator in the seed boxes and a little wheel in the very small seed box.  You can adjust the amount of seed that is deposited out of each seed box seperately, which allows you to plant different varieties of seeds; say grass and alfalfa, and do that in one pass.  The seed box holds about 200lbs of seeds, which at 20lbs/acre is about 10 acres worth. 

The manual says that you can calibrate it by putting a wrench on the sprocket and turning it 276 times and then weighing the seed that comes out, or you can wrap a tarp around it and then pull it 336' (1/10th of an acre on this model) and then weigh the seeds and multiply by ten. 

Since the pasture mix is a variety of seed sizes, and I'm not sure how well this device is calibrated to begin with, and because seeds are expensive I spent the better part of day cleaning, setting and testing the seeding rates.  I would fill it with grass seed, drag is 336', weigh the seed in the tarp, adjust, and then drag it another 336'.  To make this easier I just measured out the course and I'd go back and forth on it.

I'm glad that I did.  About 1/3rd of the seed holes were blocked, which meant that if I'd just run it in the field I'd either have bare spots or have to do two passes.  Since I've got more than 60 acres to seed, and it takes 25 hours per pass, two passes are out of the question. 

I can really see why bigger is better when you're dealing with anything over 5 acres.  Just disking the fields to prepare the seedbed took two 12 hour tractor days.  Quite a bit of work.  Good chance to catch up with the audio books, and seriously think about a bigger disk. 

Now that I've got a feel for the calibration and settings, I can change them a little each time I refill the seed box - and with careful notes, sometime next summer i'll have a pretty good idea of what mix of what plants does best.