# Let's solarize some bermuda and nutsedge



## social port (Jun 19, 2017)

Situation: playground that is overrun with nutsedge and Bermuda. Because it is a playground, no one likes the idea of herbicide.

This is a church lawn, and i saw an opportunity for an experiment. Let's see how solarization works.
What do I know about the process? Not a lot. I did some searching on TLF, and I couldn't find anything on procedure. I read this  over, and it seemed sensible enough.

No prep time on this one. It was a spur-of-the-moment idea, and I just put it into action.



I bought plastic sheeting used for painting. Medium thickness. 10 dollars per bag. Needed 4 bags to cover the space.

Before putting down the sheets, I used a string trimmer to cut the sedge and bermuda down as low as possible. The ground is uneven, so this didn't go perfectly.



Used small rocks and pieces of rubber to hold down the edges. Used some brick as reinforcement. Wanted to use stakes, but I couldn't find anything simple and inexpensive at Lowe's.

Final shot



I have no idea how this is going to go, but it will be fun. I'm thinking six weeks before removal of the plastic. Regular updates on progress, of course.

Super-Mods, if you guys think that this thread is better in the journal section, all good :thumbup:


----------



## Green (Dec 24, 2017)

For stakes, you could use landscape fabric staples, and poke them through your plastic into the ground at the edges. Nice clean, safe solution.

Btw, is your plastic all broken up? Nah, that's gravel.


----------



## social port (Jun 19, 2017)

Hey Green,
Those stakes are exactly what I was looking for, but couldn't find. I even asked two employees where they might be located: "We don't have any of those."
Guess what: I found them while searching online this morning, and they are in stock at my local Lowe's. I'm going to pick some up and then finish the treatment area off with that addition.

There are no holes in the fabric. Those are just the bits of rubber and rock that I used to keep the sheets in place. That was the best option at the moment. I'm going to like the landscape staples much better.


----------



## stakenshake (May 26, 2018)

I'm betting the bermuda will come back. It is the Alpha grass of all grass. Last August when I was working in Louisiana, there was common bermuda all around this well head. We had to workover the well and they put wooden mats covering about a 3/4 of acre around the brine well head. After 2.5 months of the workover, the mats were removed, and it was just dirt. Sure enough a week or so later common bermuda was poking its head again. I was amazed.


----------



## social port (Jun 19, 2017)

stakenshake said:


> I'm betting the bermuda will come back. It is the Alpha grass of all grass. Last August when I was working in Louisiana, there was common bermuda all around this well head. We had to workover the well and they put wooden mats covering about a 3/4 of acre around the brine well head. After 2.5 months of the workover, the mats were removed, and it was just dirt. Sure enough a week or so later common bermuda was poking its head again. I was amazed.


I would join you in that bet.
I'm hoping that the clear plastic provides extra benefit. Before I looked into it, I always assumed that solarization is based on blocking sunlight. That made sense to me, especially with respect to bermuda. It may be the alpha grass, but if you put it in shade, it will not be happy with you. So, I was planning to use black plastic.
After learning that solarization works by heating up the soil, I chose to use the clear plastic.

I do expect that this area will need to be monitored for growth, but I'm hoping to get a relatively clean slate (i.e., weed-free) starting out with this solarization intervention.


----------



## Babaganoosh (Apr 21, 2019)

Should have done half with black plastic and half with the clear plastic. It would be a good test.


----------



## social port (Jun 19, 2017)

Babaganoosh said:


> Should have done half with black plastic and half with the clear plastic. It would be a good test.


Yes, that would provide more information.

Maybe I'll have to do the same thing next year, only with this twist.


----------



## social port (Jun 19, 2017)

Stakes are in! Should be good to go.


----------



## Miggity (Apr 25, 2018)

If the plastic begins to rip and pull through the landscape pins, a playground friendly option would be to cut up an old garden hose into 4" chunks and place those perpendicular to, but under the landscape pins for more holding power. A black garbage bag placed over the clear plastic will provide a small test spot to check for effectiveness with color difference.


----------



## social port (Jun 19, 2017)

Hey @Miggity. That's a really good suggestion for holding the plastic in place. I'm hoping that the landscape pins don't lead to that kind of damage, but I will give it a try if the plastic rips.

As for adding a black bag, I'm less certain. In my analysis, that is not an ideal test. That would be clear vs clear+black, rather than clear vs black.
If there were differences in outcome, those differences could plausibly be attributed to factors (e.g., thickness of the cover) other than color.


----------



## Avalawn T (Sep 11, 2018)

Not to be a downer but are there going to be kids playing in there? That wouldn't last 5 minutes around mine and is a pretty serious hazard actually. Just a thought in case it was going to be in use.


----------



## social port (Jun 19, 2017)

Avalawn T said:


> Not to be a downer but are there going to be kids playing in there? That wouldn't last 5 minutes around mine and is a pretty serious hazard actually. Just a thought in case it was going to be in use.


It doesn't get much use right now because there is no shade, and the equipment is too hot. But I haven't asked anyone to keep children out of the area. What dangers are you seeing?


----------



## Avalawn T (Sep 11, 2018)

Suffocation hazard for sure.


----------



## g-man (Jun 15, 2017)

What about the landscape pins? I think gly will be safer. Actually a roof will be better long term.


----------



## Thick n Dense (May 7, 2019)

Is the border made of PVC?

Looks like PVC on the surface, bermuda will just spread right back in if that border is dug in.


----------



## social port (Jun 19, 2017)

This intervention doesn't seem to be very popular :lol:

The playground is in a private space, and it is not currently being used. I am merely trying to make the area more hospitable, and my hands are tied on using herbicides. Solarization seemed like an infrequently used (?) and reasonable alternative.

@g-man The landscape pins were placed in the ground yesterday. I don't think that I could make the argument that the use of glyphosate is safer than solarization; even if I could make that argument, no one likes the idea of herbicides. As you know, glyphosate has a lot of negative ideas attached to it right now, and it is difficult to convince the non-lawn-obsessed that the herbicide can be safe when applied properly. In addition, the playground has more nutsedge than bermuda, so I would probably need to use something for nutsedge, in addition to glyphosate.

@Thick n Dense Yes, the border is made of PVC, and it is resting on top of the ground. Considered from a larger perspective, the whole playground area needs an overhaul. I don't know who designed it, but it could be done a lot better. I do expect that the bermuda will creep in from the border. Periodically cutting the bermuda back at the perimeter seems doable. Bermuda that is coming up through the mulch is more difficult to control, so that is why I targeted the inner region.

I'm just trying to get rid of the weeds and to provide a cover to reduce heat so that the playground is more likely to be used. In the process, I'm learning a little bit about solarization and seeing how well it works in this situation.


----------



## masci (Apr 26, 2019)

Don't use black plastic for solarization. It should be clear plastic and you need to keep the soil below the plastic moist by either putting drip lines or lifting it up occasionally to spray. The wet heat is what cooks the weeds. Black plastic, believe it or not, is actually fine for plants. Strawberries are grown commercially by plasticulture. They lay down drip irrigation, cover it with black plastic, then poke holes that they plant their strawberry plants in.


----------



## Drewmey (Oct 3, 2018)

If they are not interested in spending too much money, you could consider burying the PVC pipe so that the top is level with the ground. Would prevent bermuda from growing under (but obviously not over). I am assuming it is a 4" pipe. If you marked the current location of the pipe, removed the pipe, dug a 4" rounded trench, put the pipe back...there would be a 4" deep barrier between the grass and the mulch. Then as the bermuda grows over the pipe, you just weed eat the hard edge. Would take time and labor but no extra material really.


----------



## social port (Jun 19, 2017)

masci said:


> Don't use black plastic for solarization. It should be clear plastic and you need to keep the soil below the plastic moist by either putting drip lines or lifting it up occasionally to spray. The wet heat is what cooks the weeds. Black plastic, believe it or not, is actually fine for plants. Strawberries are grown commercially by plasticulture. They lay down drip irrigation, cover it with black plastic, then poke holes that they plant their strawberry plants in.


Interesting. As I was planning what to do, most of what I read suggested using clear plastic, so that is why I used clear instead of black. But, just for information, you don't think that cutting off direct sunlight would be sufficient for killing bermuda? I realize that the method is different from solarization (blocking sunlight vs increasing temperature).
Also, I read that irrigation prior to laying the plastic is recommended, but I wasn't able to do that. I really wasn't planning to water this area, even periodically. How crucial is the irrigation in getting the kill?


----------



## social port (Jun 19, 2017)

Drewmey said:


> If they are not interested in spending too much money, you could consider burying the PVC pipe so that the top is level with the ground. Would prevent bermuda from growing under (but obviously not over). I am assuming it is a 4" pipe. If you marked the current location of the pipe, removed the pipe, dug a 4" rounded trench, put the pipe back...there would be a 4" deep barrier between the grass and the mulch. Then as the bermuda grows over the pipe, you just weed eat the hard edge. Would take time and labor but no extra material really.


That's a really good idea. Two things come to mind: one, do you think that a 4 inch depth would stop Bermuda from coming under? I ask, because my default assumption is that basically bermuda can spread under any and all conditions unless it is too shady or too cold. Two, the pvc is holding the mulch in place. Do you think that the rubber mulch would stay in place if the pvc was level with the ground?


----------



## masci (Apr 26, 2019)

social port said:


> Interesting. As I was planning what to do, most of what I read suggested using clear plastic, so that is why I used clear instead of black. But, just for information, you don't think that cutting off direct sunlight would be sufficient for killing bermuda? I realize that the method is different from solarization (blocking sunlight vs increasing temperature).
> Also, I read that irrigation prior to laying the plastic is recommended, but I wasn't able to do that. I really wasn't planning to water this area, even periodically. How crucial is the irrigation in getting the kill?


I had heard that if you don't see dew under the plastic, then you're not properly solarizing the weeds. Drip lines aren't needed, but if you don't see the underside of the plastic fogging, you should pull the plastic up and water it good. I'm not sure if just cutting off light will outright kill bermuda. It's an incredibly tenacious weed, with extremely deep roots. I wouldn't be at all surprised if it could go dormant in the dark and wake up again once you remove the black plastic.


----------



## social port (Jun 19, 2017)

masci said:


> social port said:
> 
> 
> > Interesting. As I was planning what to do, most of what I read suggested using clear plastic, so that is why I used clear instead of black. But, just for information, you don't think that cutting off direct sunlight would be sufficient for killing bermuda? I realize that the method is different from solarization (blocking sunlight vs increasing temperature).
> ...


Good to know. I saw some moisture and a foggy film when I went to check on the site the other day. So far, so good, I would assume. Thanks for this info.


----------



## saidtheblueknight (Jul 10, 2019)

Any updates on this? Should be about the 6 week mark now and I'm working on a very similar plan as yours, so curious how this is coming along.

Also, wouldn't it work better if the plastic sheathing did not allow sun in (unlike the clear one you used)? Yes you are physically suffocating the vegetation but still allowing sunlight in. With a plastic tarp for example, you are eliminating everything from the plant (sunlight, airflow, water etc.)


----------



## social port (Jun 19, 2017)

saidtheblueknight said:


> Any updates on this? Should be about the 6 week mark now and I'm working on a very similar plan as yours, so curious how this is coming along.
> 
> Also, wouldn't it work better if the plastic sheathing did not allow sun in (unlike the clear one you used)? Yes you are physically suffocating the vegetation but still allowing sunlight in. With a plastic tarp for example, you are eliminating everything from the plant (sunlight, airflow, water etc.)


I will update in the next week or so. I am extending the timeframe beyond six weeks. Shortly after the install, there was a 2-3 day period when temps were not as high as usual, so I'm adding some time for insurance.

The people at the church are now asking me to permanently leave the sheets over the playground and to add rubber mulch on top of the sheets. I'm not yet sure if this is a good idea.

As to your question, the best answer that I can give you is that I have no answer that is certain. What I can say is that the material that I read on solarization suggested using clear sheets, not black. 
From what I gather, the objective is not to block sunlight. The objective is to heat the soil, thereby making it an environment where plants cannot grow and seeds are 'cooked.'


----------



## saidtheblueknight (Jul 10, 2019)

social port said:


> The objective is to heat the soil, thereby making it an environment where plants cannot grow and seeds are 'cooked.'


I imagine even with a tarp you will get plenty of heat in there. The black tarp will absorb alot of heat from the sun and then direct that downwards. It would be like broiling vs baking.


----------



## social port (Jun 19, 2017)

saidtheblueknight said:


> social port said:
> 
> 
> > The objective is to heat the soil, thereby making it an environment where plants cannot grow and seeds are 'cooked.'
> ...


That is what I thought before I began this project, but I decided to set up the solarization on the basis of what I was reading.

You may very well be right, but I can't argue either way. I'm not inclined to speculate on this one, as I've been tricked by the natural world one too many times


----------



## social port (Jun 19, 2017)

OK, to give an update to this project...
I'm ready to offer a few conclusions based on my experience.

Overall, I would call this effort modestly successful, but I am disappointed in the results.

Most of the nutsedge and bermuda has browned. Presumably, all plants that are brown are dead, but I have no way of knowing with certainty.
There are a few plants that are still green, despite being completely surrounded by plants that have presumably died off. I can't quite figure this out. Perhaps the green plants have come up in the last week or two. But that shouldn't happen, at least by my reasoning.
The borders of the playground were a major point of battle. In several areas, bermuda is pushing the plastic up, and some runners have managed to come up over the plastic. Go figure, but it is not surprising, given the nature of bermuda.

I am concluding my efforts to solarize. I now have the green light to use herbicides to take care of the remaining plants. I'm planning to pull up the plastic, hit them, fix the pvc enclosure, and bring in more rubber mulch to place over the top.

A real question here is, what would happen if I took the plastic off and simply let things be? Would any of the plants that look dead recover? I won't be able to answer this question. Is solarization a good alternative to using glyphosate? Well, I can say that glyphosate offers much more control and is quicker. I wouldn't say that solarization is better than glyphosate or even equally good. But could solarization work for a renovation? I think a different project is needed to answer this question. But certainly there is potential here.

Here is what I would say to anyone considering a similar project:
1) use as few sheets of plastic as possible. Continuity is key. Areas covered by a solid sheet showed much better results than areas of overlapping sheets (don't get confused here. What I am saying is that areas where I had to connect two sheets together did not respond as well. The plants were more likely to be able to peek up at the edges of the sheets). Obviously, this is not entirely avoidable, but it is a principle to aim at 
2) use as many stakes/bricks/stones as possible to secure your edges
3) the flatter the surface, the better the outcome. Bumpy/uneven areas did not respond as well
4) overshoot your target area. If you are reno'ing 1,000 sqft, cover 1,200 sq ft or more. There should be extra space around the entire perimeter. Weeds that creep into your target area from the outside can mess things up.
5) try to make your sheets as low and as tight as possible


----------



## g-man (Jun 15, 2017)

I think you should remove the covers and let it be for a week before applying gly. Gly works via foliar transfer on plants that are growing. I'd they are dormant, it won't work and they will be back.


----------



## social port (Jun 19, 2017)

Great point, @g-man. It will also be informative to see if anything can recover during that week.


----------



## social port (Jun 19, 2017)

I took the sheets off of the playground today. I have before-and-after pictures. Some of the Bermuda was able to find holes to grow through. Same for the nutsedge.

June 1st


August 3rd 






I stand behind my previous observations (but of course, this isn't anything definitive; I'm just drawing conclusions that seem reasonable to me). The flatter the surface, the better the outcome. The fewer the sheets, the better. I'll also add: Solarization effects were minimal in shaded areas.

This was a fun experiment, but I recommend gly over solarization if that is a possibility.

At this point in the project, I have sprayed the remaining Bermuda with soul stealer CCO. I also hit the nutsedge (not sure if it will take, but I already had the solution in my tank). 
Next steps are to wait for the brown plants to green back up (if that happens at all). Then one more round of gly and/or sledgehammer. Then repair pvc border. I'll be adding more rubber mulch as the final step .


----------



## social port (Jun 19, 2017)

Further disappointment with my solarization intervention. 7 days after I pulled up the plastic, I have green plants again. I don't know if this is recovery or germination.

It is possible that someone might have better luck with this kind of intervention if the target pests were less resilient than nutsedge and Bermuda. It is also possible to improve some aspect of the intervention itself. Still, at this point I don't think I can recommend this technique as an effective alternative to gly when doing a reno. @saidtheblueknight 
Photos of the 'new' plants


----------

