I need advice for potting soil. I grow herbs, salad greens and small plants like radishes in a greenhouse of sorts, but since it's indoors I tend to have problems with pests, especially whiteflies and aphids. I know there are organic ways to handle those, but I'm thinking the source of the infestation is my soil. I've been mixing my own and including compost, and I suspect that the pests are hiding out in the compost. What kind of mix -- homemade or otherwise -- would you recommend for vegetables that won't carry bugs?

Becky, the whiteflies and gnats are there because there's no air movement. You've probably noticed you don't get whiteflies out in the garden where it's not still. If you can install a fan that is actually breezy that will help. Plants swaying in the breeze helps to firm up their stems and make them stronger.

The aphids can be washed off with water from a hose and your thumb over the end. If the tip is delicate you are washing, put your other hand behind it and wash it off that way.

Potting soil in bags these days usually have the first ingredient of Forest products, or composted bark, and other sneaky names for shredded leftover tree parts. It's not even soil, and I don't think they are allowed to use the word "soil" anymore. They use the word "mix", so don't be misled.

The best soil is real soil from the ground, your ground. I have clay and have found it to hold water extremely well in pots. Add a couple of inches of compost over the top, and then 3-4 inches of dead, broken leaves or mown grass as a mulch layer (or 2 inches in pots). If I plant in pots I use really big ones, at least 3 feet tall and 1 foot across. They don't dry out as fast, the soil stays cooler, and the roots have enough room. I use 50/50 my soil and compost for starting seeds.

Water with weak compost tea and you will create a nice bacterial environment that the plants will thrive in and the bugs will not