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Straw mulch

Posted by bill-inpnw Everett, WA (My Page) on
Wed, Jul 16, 08 at 14:52

Maybe some of you in the know can answer this. This year I put down a thick layer of straw mulch. Some of tomato plants look pretty sad.

Can straw mulch bring in a disease that can effect your tomato plants?

Thanks, Bill

Follow-Up Postings:

RE: Straw mulch

*Can straw mulch bring in a disease that can effect your tomato plants?*

I believe so Bill.
Haveing said that, and have been useing straw for some years, I can't say that I have pinpointed it as the culprit in the one case where I lost a lot of plants one year.

lots of insects tho. mites and aphids, hoppers,............stuff you find in abundace where the straw was cut.

I let the plants get strong at first before I mulch with it and the damage seems to be contained to the lower leaves until I realease or treat.
I suppose if the straw was cut and baled wet it could harbor disease tho. I try and get mulch that has been baled and barned dry.

I only notice seed on the outside of exposed bales, not any overly amount of seed sprouting in the garden.

If the seed and or weed seed only sprouts on the outside of the bale I am hopeing that any pathogens may have been also eradicated inside.
What are the symptoms?

RE: Straw mulch

  • Posted by suze9 z8b SE Texas (My Page) on
    Wed, Jul 16, 08 at 15:35

Yes, it's always possible there was something wrong with the straw, like maybe fungal spores on it (especially if it got wet and set for a while), or even herbicides. No reason to stop using straw, just know your source.

Then again, it might not have anything to do with the straw at all, and may just be coincidental. Describe "sad" -- spots, yellowing, wilting, something else?

RE: Straw mulch

  • Posted by farkee 10 B South Fl. (My Page) on
    Wed, Jul 16, 08 at 17:28

Charles Wilber, author of How to Grow World Record Tomatoes , uses thick, thick layers of straw (In Arkansas). He peels off the thick layers and uses them in squares blocks. His growth and yield are phenomenal.

It does have the effect of cooling down the soil and maintaining moisture--would this be good or bad where you are? Also keep it pulled back from the plant--I have completely rotted the stems where I did not keep it off the plant.

RE: Straw mulch

Given the weird weather problems discussed by many this year, I'd be more inclined to blame whatever problems you are having on the unusual weather rather than the straw.

I use old baled hay rather than straw simply because we have it free and straw is difficult to find nearby. But the benefits of the thick layers of mulch far outweigh any problems. JMO

Still as other have said, if baled wet, yes it can be a source of fungal infections. The solution is to crack open the bales and let them dry well before layering it in the garden.


RE: Straw mulch

I have'nt read the book.
Perhaps it explains the reason that placing thick blocks of the straw , as it would unstack from the bale, is beneficial. It seems a waste of time and straw as you could place concrete patio blocks around the base of the plants and achieve the same results.

I had neglected to mention in the post above, that I break the stacks apart fully and fluff the straw.

The reason I use straw is the insulation factor that the hollow core affords. Much like the insulation in your homes walls....the rating is only dependent on the loft of the product. If you stuff and compress the glass in whatever cavity you are insulating you lose completly the R-Factor it is rated for. It is dependent on the millions of tiny air pockets between the glass that creates the insulating properties...........Like double pane glass before the addition of Argon and E- coatings.

It would stand to reason if there were no air transfer the plants could become waterlogged?...harbor organisms?....keep air from the root zone?


RE: Straw mulch


Yes, straw can bring in diseases (I once got dodder, which is a parasite, not a disease, but still not good)
BUT, I doubt that is your problem. Having lived in Seattle myself, I know it's a struggle to get tomatoes to grow in Western WA, because they like it warm and dry. I think having a thick straw mulch would make your soil WAY too cold and wet for tomatoes.
Just out of curiosity, why did you put it down?

Carla in Sac

RE: Straw mulch

~~~ Perhaps it explains the reason that placing thick blocks of the straw , as it would unstack from the bale, is beneficial. ~~~

He used about 2" thick slabs, pushed tightly together in a 9 slab square, leaving the center out.

Clained moisture retention without smothering and no weeds. I'll be trying it since loose straw blows around too much here and can harbor too many rodents. Surprised not the same for you?

~~~ It seems a waste of time and straw as you could place concrete patio blocks around the base of the plants and achieve the same results. ~~~

Hardly. The straw would absorb moisture, break down adding to compost and reduce run off.

RE: Straw mulch

Hi Bill inpnw,

Please post pictures, then we really can get the straw smoldering.
I will be going in the Charles Wilber straw mulching direction next year for the reasons the two-daves stated including the CRW caging method Charles W. described which pushes down on the straw mulch. Great book. Aloha.

RE: Straw mulch

I use straw, hay and grass clippings as mulch much as Ruth Stout recommends only for a long time before I even heard of her. But when using them as a mulch you need to know your soil and climate. Here they help retain moisture and keep the soil cooler during the hot days which really helps. And being that it is dry here and I have sandy soil that drains well I don't have to worry about the mulch staying wet and molding and causing problems I hear others do. Did you leave a little area around the stem open? Here I mulch 4-8" deep but many say in their area 2" is enough. JD

RE: Straw mulch

Hey Folks, Could someone please elaborate on the pitfalls of using hardwood mulch for container grown tomatoes and peppers? That is what i have done, right clear to the stem around 3" thick. If this is not advisable i'm ready for a quick change!
'Wanting to learn' AL

RE: Straw mulch

To give a bit more information, I started these plants from seed and they were very healthy. I waited until late April, early June to plant. so to describe sad - instead of growing, they have stopped and have gotten spendly and wilted with leaf culf. I haven't noticed any spots yellow or black or any other leaf damage. Some of my plants have completely dried up. I made holes in the straw mulch and 3" or 4" of clear space between the plant and straw.

Why did I use straw? I've read on here that it was good to use as mulch and I wanted to build up the soil in that area more. I usually use grass clippings, but this year I've used a lot of weed and feed on the grass so that was out. And I've been having trouble with late blight so wanted to try something different this year. I'll take some photos tonight and see if I can post them. Whats funny is I'll have one plant as described and the plants to either side look great, go figure.

The straw I bought was dry and barn kept.

Thanks for all the replies everyone.


RE: Straw mulch

Bill :
It sounds more like a soil bourne condition.
In some cases your plant could contact a pathogen in the soil only in that root zone and zap a plant overnight.
One year I had a terrible outbreak of what I fear is Fuserium wilt, but I digress.....a soil test might help to find out how the ph and NPK fair in different parts of your garden.

Also have you had an unusual amount of rain up there lately? leaf curl can indicate excessive moisture.

RE: Straw mulch


I do't think it soil born as its effecting my plants in 2 different plots. The plot that was the worst, I emptied out most of my compost bin in it and the other has had only admentments added to it. All my maters in containers are doing well with the straw around them. I did the same thing to the containers as I did to my plots.

I usually get a good amount of maters in these plots with healthy plants.


RE: Straw mulch

Bill I did not have any trouble with plants in my garden until the spring before I had the worst outbreak.

I churned that tiller in until I bogged it down, thinking I will loosen the soil as deep as possible to allow the roots to go super deep...... HUGE mistake.....
I have seen weed seed never before seen in a lawn infest it after a severe, deep verticutting has brought all of that up.

After that season I planted a heavy cover crop of winter wheat, lightly turned that in by hand in late Jan. and have been building with a known source of great compost.

This year so far I notice a slight starting of the symptoms of Fusarium and have posted I was 99% sure.
I am wondering now if it is about 50 to 60% that it is FW

I hope yours is something that will be able to grow out of it as I am mine.


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