Grass Clippings for Tomato Mulch?

[ArtB]

I read here & there that folks use grass clippings to mulch maters. Won't that take the nitrogen away from the plant? Whaddyathink?

[rainbowgardener]

No, grass clippings are a nitrogen source and provide nitrogen to the plants as they break down.

What you may be thinking of is bark mulch. Wood chips are very high carbon and if they are in, or in much contact with, the soil, they will steal nitrogen in the break down process.

Grass clippings are good mulch except they can tend to mat down. When that happens, they don't break down very easily and can restrict air and water circulation. So fluff them up well, and/or mix with other stuff, like pulled weeds or yard trimmings. Lately I've been mixing mine with fall leaves for a green/brown mulch. Just like in your compost pile, greens and browns work well together and make a complete soil food as they break down.

[ArtB]

That makes sense and I appreciate the prompt response. So if it quits raining long enough to mow I know what I'll do with the clippings now. Reckon they might provide too much nitrogen?

[rainbowgardener]

Nope, re the too much N. Adding N through compost, mulch etc never risks over-doing it, since it breaks down slowly and only gradually gets in to the soil. The only way to add too much N is through uncomposted manure or synthetic fertilizers or urea.

[gixxerific]

I already have my neighbors asking if I want their grass this year. So yes I am a fan of grass mulch. I use straw and my large dry ornamental grasses as well. I have no weeds (well very few weeds ) but it all adds up to the awesome soil I have.

[feldon30]

How many months after weed-and-feed (typically 2,4D) has been applied can you safely use lawn clippings?

[rainbowgardener]

That's actually a difficult question. 2.4D is not real persistent in soil. In the soil, it has a half life of 16 days or less (depending on soil type, conditions etc), meaning in a month about 3/4 of it would be gone.

However, it is taken up by the plants, so it will be IN the grass. Horses and cattle have been killed by eating forage treated with 2.4D. I think once it is taken up by the grass, it stays there until the grass decomposes, at which point it will be released in to the environment to begin its break down process:

"2,4-D residues taken up by plants remain intact in the foliage until it is lost as litter and degraded in soils (Newton et al. 1990). Fruits from treated trees have been found to retain 2,4-D residues for up to seven weeks (Love & Donnelly 1976, in Que Hee & Sutherland 1981).

http://www.invasive.org/gist/products/h ... 0.24-d.pdf

So the residue that is on the surface should be gone within a couple months. The part that the grass absorbed will be there until the grass decomposes and then will be released in to the environment and then will breakdown as it is exposed to sun and water, over a period of probably 1-2 months, again depending on conditions.

Personally, I wouldn't use them on my veggie gardens. And since it is an herbicide, it could even be damaging to ornamental gardens.

[feldon30]

I've had a heck of a time finding grass that is not treated with Weed-and-Feed.

I may have to find a field that nobody cares about and take my battery-powered weed whacker.

[tomc]

Grass clippings can have unintended consequences. If you pile it on in thick enough layers directly on the stem of tomato, it can heat up and poach your plants. So leave a little space around the stem. and build several thin layers vs one uber-thick layer. The bed will accept water better for it.

[ElizabethB]

On the 2 4D issue. 3 years ago G sprayed the back fence line with 2 4-D. The fence grass is still dead. It also defoliated the back neighbor's ligustrums 2/3 up the trunks. What was once a solid hedge is now just tops. Fortunately she does not know enough to recognize chemical defoliation.

He also sprayed the weeds at the base of a Crepe Myrtle. It has not bloomed since then. Do I need to tell you that he has had his ### chewed and is not allowed to use 2 4D in the yard.

On the issue of grass clippings - I use them for greens in my compost bins. I find that they get too "hot" around plants unless the application is very light.

I also don't like the grass seeds that sprout up around the plants. The compost bin gets hot enough to kill the seeds.

Just my 2 cents.

Good luck

[rainbowgardener]

how could the grass clippings sprout seeds, if you keep your lawn mowed and it never sets any seed?

Most people mow their lawns well before the grass is setting seed. Normal grass clippings have no seed. If grass is coming up around the plants, it is coming from some where else, not the clippings.

[feldon30]

Do I need to tell you that he has had his ### chewed and is not allowed to use 2 4D in the yard.

The problem is, 2,4D at 2% concentration is what is generally available for Weed-and-Feed. I do not want to battle dandelions and other beasts one-by-one in my yard. Personally I could care less about growing the perfect grass yard, but the HOA minds!

Most people mow their lawns well before the grass is setting seed. Normal grass clippings have no seed. If grass is coming up around the plants, it is coming from some where else, not the clippings.

Elizabeth is in Louisiana. Assuming she's got St. Augustine, it grows in funny ways that seem to defy the laws of physics. Putting down black plastic or cardboard and building a garden bed on top of it will NOT kill it. It's way too bulletproof for that.

On the issue of grass clippings - I use them for greens in my compost bins. I find that they get too "hot" around plants unless the application is very light.

Exactly, I am wanting to get some grass clippings for my compost barrel.

[ArtB]

I forgot about the weed & feed,my wife spread some on the lawn but I have been putting the clippings on the compost pile but was going to work it in at the base of some mater plants,guess I better not huh?

[rainbowgardener]

Sprayed clippings are probably still all right for the compost pile, if you are not a purist. The 24D will be released when the grass breaks down and it will break down after that. So as long as your compost sits for long enough, it should be ok. But no, personally I wouldn't put sprayed clippings directly around your plants.

It's why I don't use other people's grass clippings, only mine, unless I know for sure. But I live 5 blocks away from my Quaker Meeting (church). The Meeting has two acres of lawn and it is completely organic, so I always have a source of untreated grass clippings if I want to go rake them.

[ElizabethB]

RBG - St. Augustine is a crazy grass. The lawn gets mowed weekly but should probably be mowed every 4 or 5 days instead. After a rain I swear I can see the grass growing.
Every spring we have the same discussion. G wants to weed and feed both the front and back. He can have the front yard but I do not want him using weed and feed in the back - vegetable and herb garden, Satsuma tree and huge live oak. So every spring we go through the same routine. G purchases weed and feed for the front and the back. We have a discussion and he returns one sack of weed and feed and gets a sack of straight feed for the back. When I need greens for the compost I have him bag grass clippings from the back yard and not the front. I know the weed and feed does not have much of a residual but I would rather avoid it.