Permeable means it s ability to allow liquids to pass through. Chicken wire is fine if you have moles/voles but landscape fabric is only mildly permeable. Testing consistently shows it slows drainage substantially. It is not ever recommended for the bottom of a bed by experienced gardeners and it would have no effect on the moles and voles anyway. 75:25 compost:loam is high on the compost side and the quality depends on your definition of "loam". Means many different things. But as long as it isn't so-called "top soil" or sand a 50/50 mixture of it would probably work. More commonly you see the recommendation for 40:60. But you will have to add more compost at least once a year and better 2x a year as it continues to shrink as it decomposes. I get the impression you aren't interested in first trying to improve your native soil and incorporate it into the bed, correct? That is the best route to go. But if not then you need to understand that overtime it can affect whatever you fill your bed with unless you made some sort of solid bottom box which is not at all recommended. But you can still make it work with a framed raised bed on top of it with chicken wire or hardware cloth on the bottom IF you keep the bed well and frequently amended with quality compost. Over time the leachate and soil bacteria will improve the soil below the bed as well. Dave

I can tell you from years of experience that trying to grow anything under maple trees doesn't work. Their root system is very shallow and too near the surface. I planted and killed more Sum & Substance hostas than I care to think about. What I do to add splashes of color is to "plant" big pots of annual flowers such as impatiens or other colorful flowers under the tree using big colorful pottery pots. I have big pots in several different glazes that I love, but I do have to take them inside my shed during the winter. I also have a hanging blue gazing globe that I also use for additional color that I hang from the tree branches of my Sunset Maple. Wind chimes are also a fun alternative.

If you have a good spade and garden fork digging out the weeds will probably take a few hours but will allow you to start using the beds this year. Once the weeds are out cover the soil with an inch or two of compost and add a quarter gallon of Steve Solomens's organic fertilizer per bed (4 parts cotton seed meal,1/2 part lime, 1/2 part bone meal, 1/2 part kelp meal). The lime helps combat the acidity of pacific NW soils and free up nutrients while the rest provides a great slow release fertilizer for your plants. Mix the compost and fertilizer into the top 3 inches of the soil and then water the beds well. Once that's done cover the beds with cheap clear plastic from home depot and secure the plastic around the edges with spare lumber, bricks or whatever you have to hand. Within a couple of weeks the soil will have warmed up and many of the weed seeds will have germinated. Remove the plastic and slice through the stems of the weed seedlings using a colinear or sickle hoe. This will kill them. Water the beds again and replace the plastic. After a couple more weeks you'll be able to kill off 90% of the remaining weed seedlings and plant your first plants into nice warm, rich soil. Good luck and let us know how it goes. SH

Another suggestion. This will cause a delay of a year, but... Kimmsr is right - it takes at least THREE shots of glyphosate to kill Bermuda in the area you want to replant. Another option, if you are willing to wait, is to overlay the area NOW with a double layer of black plastic, weight it down thoruoughly around the periphery and down the center, and wait a year. The Bermuda underneath will emerge and slowly die under the lack of light and the heat produced by the plastic. It needs to go a couple of feet beyond the edge of the future raised bed to kill the Bermuda far enough away that it will not immediately re-invade. When you build the raised bed, use a DOUBLE layer of geo-textile fabric ("weed barrier") lapping up the inside of the raised bed to the top. This will cause most of any invading Bermuda to emerge on the outside edge of the raised bed where it can be dealt with. The double layer is necessary because Bermuda can zip right through a single. That is the best protection you can apply non-chemically against Bermuda without using glyphosate.