Would it be so bad to use my silk dyes on wool and cotton? I know in the long run its probably more expensive to use silk dyes on wool, but this is just for a few skeins.

Exactly what brand of silk dyes are they? The answer to your question will vary dramatically by type.

Most silk dyes are acid dyes, most of which will not work on cotton at all (that is, they will not produce a washfast result), regardless of technique, but will work fine on wool. In contrast, Procion H will work fine on cotton, with steaming (it is much less reactive than Procion MX, so needs the greater heat to react with the fiber). Remazol (or vinyl sulfone) dyes, such as Jacquard Red Label Silk Colors and PRO Chemical & Dye's Liquid Reactive Dyes, are said to work on cotton at room temperatures, again using a high pH, but I haven't yet tried this myself, and they will probably work better at 140 degrees F. (60 C); they will certainly work on wool, however, and as true reactive dyes, too, at hot, mildly acid conditions. (Do not subject wool to a high pH.) On cotton and silk, the Remazol dyes make the best dischargeable blacks.

However, Aljo's Alcohol/Water dyes, which are used for silk painting, are Basic dyes (which means they hold a positive charge, unlike other dyes), and will not work at all on cotton unless it is mordanted. Oddly, you can accomplish this mordanting by dyeing the cotton first with direct dye (I don't know if this is true of all direct dyes), as well as by the traditional mordanting techniques used with natural dyes.

I also have some wood and reed dye in my stash and am thinking those might work well, too.

Jacquard Wood and Reed Dye appears to be Basic dye, like Aljo's Alcohol/Water dye. I find the toxicity of some of the dyes in this class to be sufficiently alarming that I advise against using Basic dye in a kitchen; I think it should be used only in an art studio or laboratory in which no eating is ever allowed, in addition to the usual precautions, respirators, fume hoods, etc. It is very possible that some members of this dye class are actually much safer than the ones with which I am familiar, but I have no information yet indicating that this is so. For reasons why I find these dyes so alarming, see my doctoral thesis....