We used dried grass from our lawn mowing. We don't use any chemicals on our lawn. Hubby mows it and then rakes it up into long narrow piles to dry for a day. He bags extra grass for our chicken coops or for garden mulch. You have to put it down pretty thick.

I use straw in my raised beds. Up in Reno we are also in our third summer of drought, so anything to help with cutting down on the watering is fair game. The straw mulch helps a ton with water conservation. I put it on pretty thick - say 4-6'' and it settles some over the course of the summer but it cuts down on the weeds by 2/3. You can get a bale at your local feed store and it really lasts.

Humus is great for the soil. A good amendment but not much good for mulch as it is too fine textured and breaks down quickly. Straw and/or hay are often considered the ideal garden mulches because when laid on thickly they not only suppress weeds and retain moisture but as they decompose over the garden season they also provide soil benefits..

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Dave

Today we will be mulching with a system of cardboard and wood mulch.

But WAIT! She sez. I've been told NOT to mulch with wood chips!

The fear of mulching with wood chips is somewhat, thought not entirely, overblown. But, cardboard is our friend here. Read on.

The cardboard is a weed barrier, and also keeps the bark mulch from working its way into the top inch or so of soil and creating anaerobic conditions right there at the verge.

The bark is to keep the cardboard from drying out and blowing away, and it also just looks nicer than slowly decomposing cardboard boxes.

The whole system keeps the soil cool and moist with much less water, encouraged earth worms, and discourages ants. I wouldn't suggest doing this in, say, Alaska or Maine, or anywhere where cool damp soil is already a problem. But in the hot dry - works great.

You will need to check the mulch every once in awhile and make sure it is staying moist. I've never had it dry out - but if you are in drought conditions, it might be a wise precaution.

Another situation in which this doesn't work too well would be any plot that is overhead watered. But for a drip irrigation system in a square foot gardening or raised bed situation, it works great. Just aim the emitters so the water goes into the open areas/catchment basins around each plant stem (or put the mini soaker for row crops like carrots under the cardboard).

I make these catchment basins about 8 to 10 " across for eggplants and peppers, but about 10" x 18" for tomatoes - because I plant tomatoes on an angle. But I digress - and I will explain more about drought proofing tomatoes later.

So back to the mulching.

Go buy the cheapest bark mulch you can find. If your municipality has a mulching facility, you may be able to get some from them. I got mine for $2.50 for a big bag - like 2.5 cu ft - at Home Depot or Lowe's, and I think one of them has it on sale for $2 now. Don't get black; get a light color if possible. Mine is med brown in color.

Note that if I was starting with an empty raised bed, I would just lay the cardboard out and give it a good soaking, cover it with the mulch, then pull back and poke holes wherever I want to put a plant. It's easy to rip an opening into wet cardboard, but you can use a box cutter for the sake of neatness and precision. Leave open rows between cardboard slabs for things like carrots etc.

However you've already got the garden in so you'll need to fit the cardboard around existing plants. This is how I do that:

Take some brown cardboard boxes - like the ones Amazon ships stuff in, or old moving boxes.

Flatten them. Break them down into manageable size pieces. I used a box cutter to cut them into strips 12" - 16" wide, whatever is convenient and according to what's planted in your raised beds. Soak them thoroughly - lay them out in a tub or large plastic container like you keep gift wrap in and flood with water. Don't worry if they've got brown paper packing tape on them, that will soak off when you wet it and can be easily discarded. Plastic tape should be ripped off prior to soaking though.

Meanwhile water your raised beds (one at a time so they don't have a chance to dry out). Take pieces of soaked cardboard and lay them out around and between your plants. You can easily rip out chunks of cardboard to go around plant stems because its wet. Leave enough room for the drippers to do their work (you do have drippers only at each plant, right?) If you are using mini soaker hoses for row veggies, those can go under the cardboard.

I lay the cardboard 2 layers thick on the ground; one layer (of corrugated brown cardboard) MIGHT be ok in a raised bed - but you'll have to replace it more often.

Tamp the cardboard down or press firmly so it is in good contact with the soil. Which, btw, needs to be fairly level, except for water catchment basins (depressions in the soil) right around your plants to help funnel what water there is to them.

For the following step - WEAR GLOVES. You can get tiny little splinters from wood bark mulch, and every now and again I come across a piece of scrap aluminum. Plus, it keeps crud from getting under your nails.

So, now I go ahead and cover the still damp cardboard with mulch. The cardboard is your weed barrier and will eventually break down into the soil (which is a good thing). It usually lasts a couple of years before I have to pull the mulch back and lay more cardboard.

The bed needs to be thoroughly watered - not muddy but damp all the way through, and the cardboard needs to be wet, otherwise you are sealing in the dry!

Make sure it is well covered with the mulch. Any bit that peeks through will dry out prematurely, and it will wick moisture instead of preserving it.

Finally I spray some water all over to help it settle. From now on your drippers will do the work. In drought, you might want to wet the whole bed down as appropriate if the cardboard shows signs of drying out.

This works perfectly as a weed barrier, and while it breaks down just as fast as plastic (maybe even a little faster), it will let moisture through if it rains enough, and when it does break down, it adds to your soil. It's also free. You will need to occasionally add bark mulch to the top as that will also break down, albeit very slowly.

HOW TO DROUGHT PROOF TOMATOES BY PLANTING AT AN ANGLE:

I plant the root ball about 8" to 10" deep and angle along the stem until just the top couple of leaf shoots would be left above ground. Strip any leaf branches that would be buried. The tomato plant will root all the way along that stem. This makes for a stronger plant that is FAR more tolerant of drought. So I leave my catch basin such that it runs all the way along that stem back to where the original root ball is buried.

The larger the plant when you put it out, the more stem you will have to root. I actually prefer larger plants for this reason, even if they're a little leggy, by which I mean a long stem, but not overly thin. You want a good thick central stem - but even if the plant has gotten "too big and leggy" to transplant, it will likely transplant well using this method. So a plant that is a little leggy will do very well planted this way because all that will root, and where the stem comes out of the ground will grow in good and strong, even when the original plant was a bit leggy. Of course if the central stem is REAL thin and weak, it will break off underground. So - not too leggy.

Finally, this method of mulching also protects from many soil borne diseases because the soil is under the mulch and won't splash up onto the leaves to infect them.

It encourages earth worms - but it may also encourage slugs. The one good thing about it is that they are easy to find and pick off.

However, in our drought-stricken regions, I doubt slugs will be much of a problem.

Next year I'll be building some raised beds here that are self-watering and I will use this system to mulch them. I've been doing this for about 10 years, ever since I moved back to an urban environment where grass is better left on the lawn to fertilize itself, and things like straw and hay are way too dear to be trying to get enough for mulching. The cardboard is free - in a raised bed it doesn't take that much, and the wood mulch is attractive and cheap and fairly long lasting.

Also, just as a note - grass clippings tend to mat. This will make water run off instead of soaking in. If you have too many grass clippings to just leave on the lawn, they are much better off going into your compost bin - mixed well with browns like leaves, or shredded paper or cardboard.

The best garden I ever had was the year I had access to water-spoiled hay from the local riding stables. There was MOUNDS of it. I mulched my huge 20x30 garden plot a foot deep. There was drought that year. It was great. And as weedy as hay is, there were no weeds to speak of - it was just too thick for anything to get a good grip. Anything that did poke it's head up was easy to pull. But hay and straw are very expensive in urban areas. And if you EVER mulch with hay, you'd better mulch forever, because of the weed seeds in it. This was an old field full of bindweed and giant hogweed - this stuff:

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Take a look at this website for more info and lots of pictures, including what it can do to your hands and skin:

Put on your hazmat suit before you go outside

So with that stuff growing out there, I figure whatever weed seeds the hay might have introduced had to be harmless, in comparison!

Here is a link that might be useful: An Official Anti-Giant-Hogweed Page

This post was edited by zensojourner on Sat, Aug 9, 14 at 18:04