Before I actually had children or a house, I had visions of a perfect family and a perfect home. I dreamed of soccer-playing children, with golden hair like my husband's, keeping me company while I gathered flowers from my abundant gardens.

Even if my oldest son's autism had not become a reality in our lives, none of that perfection was to be for us. Well, I do have a garden, but no time to tend it. I did get golden-haired children. But as for the rest of it: They are indoor, cerebral types who would rather figure out how to get a computer to draw a soccer ball accurately than kick a real one.

One thing I do have from my dreams is lush grass. I'm not really sure why, because I don't have a lawn service like the rest of my neighbors. I don't weed and feed regularly, and I don't have an "irrigation system," unless you count a battered sprinkler. I don't even own a decent mower with a bag attachment. I have a rotary push mower, the kind that the original owner must have used 120 years ago, and two strong teenage sons.

Last summer was the first time I had Nat, my autistic son, do the lawn.

Why not lawn-mowing? He already knew how to vacuum. To my mind, they were similar: You push a machine forward, then backward, over a surface you are trying to make more neat and orderly.

That is how my mind works. It is not how Nat's mind works. For Nat, it is extremely difficult to generalize skills from one task to another. To him, the parts of the chore that equal vacuuming are specifically related to vacuuming only. Lawn-mowing, for him, was a brand-new concept, and I realized that I had to start with simple steps.

"Go up and then down, Nat," I said, showing him how to do one row, turning, and showing him the next. "You push the mower, until you get to the garden's edge," I showed him the edge, "and then you turn around." I repeated this many times, because repetition is the other key to his understanding things.

I stood back and watched him go. First row: straight, excellent.

Then, too far into the flower bed. I saw that he had clipped a few emerging perennials. I sighed. I watched his turnaround: uneven.

This threw him off and he began to jut outward from his previous straight line. "No, Nat, here!" I pointed animatedly to the tire track. He dutifully looked down at the grass. I wonder what he saw; he just kept right on in his crooked line. I gently pulled him back to where he should be.

After a few more minutes of this I was sweating more than I do when I mow the lawn. And I felt my temper rising. Before me was path after crisscross path cutting through the lawn, like a giant tic-tac-toe game. Suddenly very tired, I grabbed the patio chair and sat down for a moment.

Okay, I thought. What's the real harm here? He's getting exercise.

Some of the lawn was actually being mowed. It didn't matter that there was no pattern to the mowing, because it is better for the grass if the mowing pattern is varied from time to time. I had read this somewhere, and it made intuitive sense to me. Even the part in your hair should be changed every now and then or it eventually becomes flat and stale. I took a deep breath and closed my eyes, listening to the clipping sounds and smelling the oniony-sweet scent of the cut grass.

After about 40 minutes, I declared Nat finished. I walked the length of the yard, surveying his job. Here and there were tufts of forgotten grass, quite a few in the shady areas where you can't see what you've already done. There were also areas that had not been touched, toward the back boundary and the sloping part. I took the mower and dragged it over a few obvious rough areas. Then, when finished, I glanced around. The overall gestalt was green, smooth lawn -- if you kind of squinted at it. I broke into a grin and rushed inside, eager to tell my husband how it went.

So this year, as last, Nat mows the lawn. Though far from perfect, it is certainly a healthy lawn. It could be because we don't do a whole lot to it, or on it, like playing soccer. It could be because we have just enough sun and plenty of rain. But I like to think that our secret is that with autistic lawn-mowing, you never mow the same pattern twice.

Susan Senator lives in Brookline, Mass., and is the author of the upcoming book "Making Peace With Autism."