Weeds and work

Imagine I own a house – a pretty structure that holds all my treasured belongings. Around my house is a lawn. I don’t take excellent care of my lawn, though I do try to make some attempt at keeping it healthy. For the most part though, I kind of assume it’ll take care of itself. I find I’m not motivated to devote time each day to lawn maintenance and I consequently cannot claim to have the most beautiful landscaping in my neighborhood.

When I was mowing last weekend, I noticed my yard is filled with weeds. And I decided it was a perfect way to describe what I do. It was going to take a long time to write out and it’s not like any of you have expressed some great curiosity as to my area of research. But I’ve thought about it more and more, so the time I could spend mowing and raking right now will instead be crafting an analogy for my job.

Weeds aren’t good. We must agree to the truth of that statement to structure the foundation of my argument. They grow too quickly, use all available resources, and crowd out the pretty grasses we want to be there. In the absence of much weed knowledge, let’s say that they also change the structure of the soil. They’re harder to cut than grass. We hate them and all that they stand for.

Our goal, therefore, is to rid my lawn of weeds. Now there are multiple strategies for attempting this project. I have three basic ideas.

1. I teach Chienne to dig out the weeds, removing as much of the root structure as possible. She will then carry the weeds to a trash receptacle. Obviously training my hound to do this will be non-trivial, but let’s say that she’s fully capable of doing the job if I can tell her exactly where to dig.
   
2. Using the laser that produces Sprout’s favorite red dot, I have added some element so that when the light is directed at certain spots on the lawn, the weeds are damaged. If the laser treatment is applied for enough days and for adequate time, the weeds in that spot should die from the structural damage caused.
   
3. I buy weed killer and spray the entire lawn. I hope that the chemicals don’t damage the healthy grass and have some targeting mechanism by which weeds are selectively killed. I must accept, however, that some damage may be done to the entire yard in this systemic treatment.

For focal treatments (options 1 and 2), there is an obvious need to isolate the weedy areas. In order to sic Chienne on the evil weeds or to focus the laser on the appropriate areas, I have to know where they are. I decide, therefore, that I’m going to take a picture of the lawn so I can develop some treatment plan. Now my plan would vary depending on whether I was going to use Chienne or the laser, but the overall premise is the same. I want to know exactly which parts of the lawn are bad and which are good.

So I take my digital camera and photograph the yard from many angles. Then I come in and look at those pictures and while I have some idea of what’s going on, it’s hardly a complete picture. Sometimes the weeds look a lot like grass so the boundaries are unclear. There are many areas which display partial volume effects (i.e. within a given region, there appears to be grass mixed with weeds that defies strict categorization). For those areas, I need to decide whether I want to treat them or leave them alone. I’m also a bit confused about some areas that might be weed but might just be a different kind of good grass. So I want more information.

Luckily, there are many people who know a lot about weeds and how to visualize them. So I ask someone to take an overall pollen map, hoping that I can differentiate between different plants based upon the airborne stuff they produce. I decide to rent a machine that can give me some basic idea of the chemical composition of the lawn. This is highly specific to weed/grass differences, but is rather difficult and time-consuming, so I can only afford to get a couple of regions done. Let’s say weeds are different temperatures than normal grass, so I take a thermal image. Perhaps weeds use more water so I create a map based on moisture usage. Maybe worms are drawn to the weedy patches more than normal grass, so I get a profile of worm populations across my yard.

There are people who devote entire careers to understanding worm populations, water-usage profiles, pollen counts, etc. We hope that each one will offer some valuable information, but we’re simply not sure if that’s the case. While they seem to work overall, every lawn is different. Perhaps on the day I took my chemical picture, the weeds weren’t growing very fast because the sun wasn’t out. Maybe it had just rained before we took our picture of the water, so everything looks really wet. Maybe the worms had other plans on the day we were interested in them and so the worm map isn’t truly representative of their overall behavior. There are many questions that can and should be answered about the individual methods.

Therefore, many people spend a lot of time studying healthy lawns. It’s easier to differentiate between grass, driveway and hedges so if you apply these pictures to those situations, you can refine your imaging capabilities. So that’s really good and very important, but my lawn is sick. I’m the one who needs help getting rid of my weeds, so let’s use some resources to focus on making my lawn well again. So that’s what I do – I study sick lawns.

My focus is this: Given that there are so many ways to study lawn behavior, can I take all those pictures (representing the best technology we have at the time) and get an excellent idea of what parts of the lawn are bad and which are good. Then we can rid ourselves of the bad while retaining the good. Easy aim, difficult problem. The pictures are huge and complex and require a lot of time and energy. But I develop and apply methods that analyze and combine them to try to isolate the weed patches.

How do I know if I’m right? Someone says that plants can be categorized based on cellular structure, so we mark on some picture where we’re going to pick weeds, go to exactly those spots, then pluck a piece of plant from the ground. Then someone goes off and analyzes those samples – they can define cell structure, cell number, cell properties, even the genetic or protein profile of the plant. This represents the gold standard of truth on what’s a weed and what’s grass. So we can compare all our pictures to these results and see if we’re actually seeing the truth of the situation or if our pictures are somehow flawed.

Project M considers all the pictures I can think of with the goal of telling Chienne where to dig. Digging is the way to go since some lawns tend to have a single, large weed patch. The pictures are disturbing. One expects to see a happy, green lawn and notices a large abnormality that looks different than normal grass and appears to send out tentacles of weeds in all directions. In graduate school, I looked at previously-treated lawns that saw a recurrence of weeds. We’ve chosen to focus on the initial occurrence of the unwanted growth for various reasons, but the pictures we take could offer additional information that would aid in the weed removal.

Project X, however, considers lawns that are sick in a different way. Instead of a single, large region, these lawns have multiple, smaller patches of weeds. So instead of a focal area that invites digging, there are an overwhelming amount of small spots that are wrong. And while it’s good that they’re smaller, the pervasive nature of the weed infiltration makes me ill. I’m not used to weeds appearing that way on my pictures. It bothers me.

When presented with lawns such as these, one borrows Sprout’s laser to use light and sprays the lawn with chemicals. The weeds are obviously spreading and appear at unpredictable locations. So a full lawn treatment is necessary. Therefore, any information I can give about where the weeds are located is rather moot. The whole lawn will be treated the same regardless.

The point, therefore, is more subtle. It turns out that if you have a new lawn, treatments cause some secondary damage. The lawn isn’t as healthy as we’d like as it matures, even if the weeds are removed completely. In an attempt to use some additional chemicals to protect the young lawns, we want to know if there are a set of pictures that can show this secondary damage that might occur. Since we don’t want to practice on new lawns, we instead focus on established lawns.

But I meet the owners of the house and I look at the lawn in front – ugly with weeds growing in tiny patches throughout, and I ask if I can take some pictures.

“I can’t really do anything to help your lawn.” I say. “I pray the treatments that will be delivered are successful. I want that very, very much. So in the hopes that we can help some younger lawns, I’d like to inconvenience you a bit by taking some pictures. Is that OK? It won’t hurt the lawn at all, but it also won't provide the help I so wish I could offer.”

I don’t know why the weeds show up, though there are people who are working on understanding that more. I understand a bit about how certain types of weeds behave once they exist, but that’s more to correlate with my pictures. I basically want to create a map of where the weeds are. And hope that it can help the lawns I see and add to the literature on how we might use various pictures to make lawns well again.

It seems important to me. Having met some home owners, it seems a lot more profound and urgent. And having crafted this analogy, I find that my tolerance for weeds is very, very low.