I always used to mow my lawn in spiral fashion (albeit a squared-off spiral) – that is, mowing along the outside edge first and then just inside the first cut on the next pass, then just inside the 2nd cut on the 3rd pass, etc. Recently however I have begun to mow boustrophedon – a simple back and forth pattern. And I seem to be finishing MUCH more quickly. So I’m wondering, is it really noticeably shorter to mow back & forth vs. spirally? Does the spiral travel path add that much more distance?
Can someone work out an example for me – assuming I have a rectangular lawn that is 50’ by 100’, and a mower with a 2’ deck, and that there is no overlap on each cut, the boustrophedon path will be 25 x 100’ = 2500 feet, right? So how far will I have to travel to mow the lawn in spiral fashion?
P.S. if the math is easier with other numbers, please substitute. And as you may have guessed, I was always lousy at calculus.
Spiralling is weird. I mow boustrophedon, with the modification that I mow a line first forward, then retrace the line backwards. Not that that speeds up the process, but it catches the grass that was trying to escape by bending over in the direction you originally headed. I’m smarter than grass.
A slight hijack. I have certain neighbours who mow diagionally, then mow perpendicular to that, so it forms a cross-patch pattern. I consider that anal. Am I right, or not right?
Assuming you’re traveling the same speed in both cases, and the “overlap” you refer to in the spiral case is similar to the overlap you’d allow going back and forth… it should take exactly the same amount of time.
You say you seem to be finishing quicker. Can you check it with some stopwatch style precision?
Forget the distance, the number of turns alone will slow you down appreciably. Every time you turn, you stop momentarily. When you mow in a line you make one turn at the end of every row. That’s effectively 2 turns to mow 300’, one at the end of the first row and one at the end of the second. When you mow in spiral you move 100’, turn, move 50’, turn, move 100’, turn, move 50’. That’s 3 turns for every 300’. As the remaining area gets smaller the discrepancy gets larger. Even on the last runs in a straight line pattern you still only make 2 turns ever 300’. With a spiral you might be making 10 or 20 turns to mow 100’.
Use middle dimensions for the rectangle for each ‘circuit’. That means the mower starts out 1’ away from the edge of the lawn.
For the first circuit, the mower travels 49’+(99-22’)’+49’+(99-22’). Note that I’m taking into account the corners. The next circuit would be 45’ + (95-22)’ + 45’ + (95-22)’, and so on.
Bunging the whole lot into Excel gives this badly formatted list:
thanks Rabid Squirrel, for working out the math. Looks like Blake has it right – I hadn’t even considered the amount of extra time for turning. And as you pointed out, it’s not just the turns – lining up the next cut is more complicated in the spiral than in the back-and-forth.
Not In Anger, you are right, the way your neighbors cut their grass is anal!
With rotary-type mowers, you generally have to mow one direction, and then make another pass perpendicular to cut the grass really even. That’s the reason that commercial lawn services mow business parks that way–the second time hardly takes any fuel, but evens out the grass height a lot… Spool-type power mowers can get it perfect on the first pass, but they cost lots more money.
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You just wanted an excuse to drop “boustrophedon” into the conversation, you sad dictionary-swallower you! (I ought to be fooling around with [ font=symbol ] or something, but life’s too short.)
Still, with a name like aesop, I guess you can be forgiven
I have a mulching mower, which means the mower needs to go back over piles of grass at least once and all the grass needs to blown to the inside of the section of lawn being mowed so that it’s in one place to be “mulched” and doesn’t blow all over the sidewalk or the deck or the neighbor’s yard.
But you bag people and leaf-blower people may not care about such things…
My empirical experience is different than the theorists above posit. I used to mow back & forth, then switched to a decreasing spiral, starting around the perimeter of my yard working in. I cut my mowing time from 50 minutes to 40 minutes very consistently.
In rebuttal to Blake’s theory
When you mow in a spiral you’re only turning 90 degrees, not 180, so you don’t have to stop at all (God forbid you would have to stop your car every time you turn a corner). In boustophedon (new word for me) you have to completely stop, if only briefly.
My spiral rounds off after a couple of passes, I don’t try to keep it square, and that speeds up the turns. Keeping it utterly square would cause you to lose a little time in the turn.
The most time-consuming was when I mowed back & forth on a diagonal, and alternated the slant from cut to cut. Forget that crap unless your competing with neighbors.
Back before I got lazy and hired a lawn service, I would mow in a decreasing spiral with the blower facing out. (Except for the first circle, which by necessity pointed inward).
This distributed the grass clippings very evenly across the yard. Thus I avoided the necessity of raking and bagging the clippings - which saved a <i>lot</i> of time and the part of mowing I hated.
