Part of your choice depends on your situation. Preen is a pre-emergent, so it won't help with weeds growing from established roots or runners. If you are buying soil, you just don't know what you may have in there. (BTW, Preen is just corn gluten. You can often get it at the farmer's coop or feed store in the un-branded and cheaper variety.) In this area, weed cloth makes an excellent bedding material for invasive grasses and grasses like bermuda easily poke holes in it from underneath. It's a disaster. A layer of newspaper would be near worthless. BUT -- that's here. Different places have different challenges. I use a thick layer of mulch (old straw, leaf compost, etc.) At 10" deep, it suffocates many of the weeds. Not all, unfortunately, but it puts a serious dent in them. There is no such thing as a weed-free garden but you can get close with planning and routine maintenance. 12x5' should be fairly easy to maintain and is a great size for a first garden -- large enough to get some variety but not so big it overwhelms you. 10-15 minutes a day in the garden checking this and pulling up that and you will do well.

It's been so hot here lately, I'm not surprised. It might as well be July! But since it's backed off from 100, where tomatoes tend to just stop -- it would continue producing for a little longer if this weather holds. When it gets cold and when it becomes more like fall, you'll see them slow down, dwindle and then die. Though today's weather is beautiful! I don't think you have to do anything for your strawberries in Sacramento. They would over-winter as-is, and will probably continue producing for awhile, I would guess.

Glad to try to help! I start at least 1 new bed somewhere every year. "If I use cardboard and whatever OM I can come up with, and then the finely shredded wood chips (can that be bought?)." Yes, finely shredded mulch that isn't painted a designer color (takes longer to decompose, and you probably don't want to 'eat' decomposed paint or dyes) shouldn't be hard to find. "Will I be able to plant next spring??" Yes, I always do. A layer of something moist and green directly on top of the cardboard (like grass from mower bag, small yard trimmings, produce scraps from kitchen) will give the green/brown (the paper/cardboard) balance needed for speedier decomposition. Put under the mulch, you'll never know it's there, should be 'dirt' by spring, at least in appearance and texture, but you'll know it's compost/humus. Put tons of leaves on top when you get them in the fall. I>"I find it hard to imagine all of that would decompose so quickly. If so, would I add soil on top before planting?" This depends on the weather, climate, and mix of stuff you put there, but a reasonable expectation. "And before laying down the cardboard or papers, I'd want to cut it all down as much as I can?" Yes, this will help the smothering stuff be best able to contour to the soil surface, blocking the air and light and space needed for stuff to grow under there. "Oh, one last question - when would u start the lasagna layers? ASAP? " I would, but it's up to you. The longer it has, the more decomposition possible. "Was gonna let my sad tomato plants go to see if I could get any goodies from them..." If you think you can work around them, they shouldn't mind, probably like it. Maybe pull stuff around the base, then smother nearby, filling in those holes later when the toms are finished? Up to you, but likely do-able. "What kind of OM can I buy at a store? " Mulch and compost, but if you start looking around you'll probably find stuff. As long as you mow before you see seeds on the grass, there will be few seeds in the grass, which won't be able to grow through all of the stuff on top anyway. As you stir things up planting and harvesting, some seeds may end up on the surface and sprout, but once you gain control, it's easy to pull unwanted sprouts when you see them. I've never caused an infestation of unwanted grass doing this. After you've gotten started, you can add kitchen scraps as you get them. Dig a little hole (but not deep enough to pierce the cardboard until next spring) for them, cover back up. Nobody but you will know you're "sheet composting." The more stuff like that you can add (greens as opposed to browns like the cardboard and mulch,) the quicker it will all decompose. Green + brown = fast compost. Green alone or brown alone = very slow decomposition, less desirable end-product. I usually proofread, but it's lunch time, hope...

Cover those "weeds" with newspaper or cardboard and cover that with a mulch material. The newspaper/cardboard deprives the "weeds" of the sunlight they need to grow sp they die and put back into the soil the nutrients they took out to grow. Soils left unmulched tend to grow a lot of what we call "weeds" which are meant to cover bare soil in an attempt to 1. prevent soil erosion, 2. retain soil moisture, 3. add organic matter to the soil, and 4. aid soil temperature control. Mulches do all those things as well and prevent unwanted plant growth we call "weeds".