Cow manure is not a mulch, though it's a wonderful soil amendment. My dad grows in pure composted manure spread on top if his lawn. But if any weed seeds blow in they will love it as much as the veggies. Best cheap/free mulch I've found is newspaper weighed down with burlap. Last year I used hay on top of burlap, the hay tends to blow away and the burlap decomposes within a year, newspaper takes longer and will blow away. Ants tend to build nests under the burlap but the worms love it too, this year I pulled the decomposed burlap off and left the sides of the mounds exposed, put what little hay I had just around the plants (didn't want to hold a lot of moisture in, June was so wet), didn't replace the burlap and the weeds (crabgrass, ragweed, and bindweed) are terrible, I'm going to have a big cleanup job when harvest is done. But for strawberries the best mulch really is straw if you can find it (and I thought $7/bale was high!), in my zone I use leaves and pine boughs to cover for the winter. I got small bales of straw on sale last year after Halloween, also that's the time of year to ask on Freecycle and Craigslist too. Leaves just mold and cause mold/disease on the plants when used in strawberry bed. Pine needles might be good alternative to straw, I just don't have enough clean ones around here with the oaks and maples mixed in with white pine and hemlock.

edit: well, it looks like that PDF access does not work, so here is the ref: "Impact of Mulches on Landscape Plants and the Environment --- A Review" - by Linda Chalker-Scott J. Environ. Hort. 25(4):239-249. December 2007 Mulch Problems --- Real and Perceived Acidification. Organic mulches such as wood chips and bark are thought by some to be soil acidifiers. No scientific research supports this, and in fact studies refute this perception. One study found neither pine bark nor pine needles had any affect on soil pH (51). A second report (60) found bare soil to be more acidic than soil covered by inorganic mulch, and that shredded bark and wood chips were least acidifying of all treatments. Similarly, a year-long study found that the soils under organic mulches were either more alkaline or not affected by mulch treatment (100). ItâÂÂs likely that in artificial conditions, such as nursery production, that woody materials do have an acidifying effect when they are used as part of a potting medium. Release of phenolic acids is one stage of the decomposition of woody material, and if this material comprises the bulk of medium then acidification is likely to occur. In a field situation, however, where the woody material is used as a mulch (and not worked into the soil), any acidification will be localized within the mulch layer and have little effect on the vast underlying soil environment below. Thus, soil acidification due to mulching with woody plant material is unlikely to occur under real world conditions. Greenly, K. and D. Rakow. 1995. The effects of mulch type and depth on weed and tree growth. J. Arboriculture 21:225-232. Iles, J.K. and M.S. Dosmann. 1999. Effect of organic and mineral mulches on soil properties and growth of âÂÂFairview Flame Râ red maple trees. J. Arboriculture 25:163-167. Pickering, J.S. and A. Shepherd. 2000. Evaluation of organic landscape mulches: composition and nutrient release characteristics. Arboricultural J. 23:175-187. Here is a link that might be useful: Impact of Mulches on Landscape Plants and the Environment This post was edited by Fascist_Nation on Tue, Oct 22, 13 at 10:45

I've used both straw and hay mulch for years. As mentioned above, the secret is to lay it on thick. If you put it down 6 inches thick in spring, it will be reduced by 80% by late fall. I've never used straw that was seed-free, but it has a lot fewer seeds than hay. The thing is, permanent mulch gardening is something that you need to stick with. If you mulch even one year with hay, you're going to get a million weeds for years thereafter if you don't continue the mulching. I usually just peel the squares off the bale and lay them out like floor tiles. If I have a decent supply of cardboard, I may lay that down first, but again, the secret is to lay it down thick, and keep adding to it as required. I also pile on shredded leaves, pine needles, lawn clippings, whatever I can get my hands on.

I copied this from an article in a small rural newspaper while travelling. Not all new gardeners can count on cultivated soil for their plants. Some may be burdened by limited space or rocky ground. As a result, whether a new gardener or a veggie veteran, bale gardening may be the way to go. Growing vegetables in bales really works because bales provide the two things seeds need to grow. "For seeds to germinate, all you need is heat and moisture," said John Sims of the Farmer's Cooperative. In 2005, The Post published an article on bale gardening, and it has been one of the most frequently read articles at The Post Online. Tomatoes, peppers, squash, cucumbers, green beans, melons and a host of other plants grow well in bales. The Farmer's Cooperative, Southern States, and Danny's Builder Supply in Centre all carry wheat straw bales. To plant a hay bale garden, first, around 10 days before planting seeds, place the bales in a sunny location. Soak them with water for three days. On the fourth day, apply 5 oz. of fertilizer, followed by a couple more days of watering. On the seventh day, apply 2.5 oz more fertilizer, followed by a couple more days of watering. On the 10th day, apply a cup fertilizer and lightly water into the hay bale. On the 11th day, plant seeds by applying a three-inch layer of top soil or potting mix to serve as a bed. Each bale can hold two tomato plants, four pepper plants, six to eight cucumbers, three yellow squash or 12-15 bean seeds. Bales can typically be used for two or three seasons.