1. You won't want the sand, dirt or clay in the container. You don't say what kind of sand, but if is the small particle stuff like play sand, don't use it please. What you want are larger particles to promote good drainage. This thread explains in detail. Given what you have on hand I would say the peat moss and perlite would be your best bets and then go with an 8" deep container as it will support a low oxygen, water saturated layer at the bottom(you will understand this better after reading the thread linked to above). This mix will also be fairly light compared to say, clay and gravel. I would have said to just use the potting soil mix you have, but the term is vague and I don't know what ingredients are in it. If it looks like a really nice, loamy dirt, don't use it. If it is mainly peat then go with that. If you got really lucky and it is mainly small bark pieces, definitely use that. 2. The herbs don't need any more protection than anything else does from the wind, but dill can get fairly tall (2-5' depending on the variety). It is a fairly 'airy' plant so doesn't catch the wind all that well, but I generally try to have other plants propping it up or something the prevailing winds can blow it into and stop further movement. Again, the dill will likely survive the winds, but it can be blown such that it is now hanging well over the container instead of remaining upright. In terms of it being edible, this won't matter, but if you want a 'neater' appearance you might care. I am really not sure how to support it all that well in a deck railing scenario. 3. The dill and other herbs won't be stunted in the container at all assuming you use a sharp draining potting mix and fertilize a bit. In fact I think you may find the opposite to be true. Many herbs seem custom made for container growing as many ground soils are too wet and in zone 4 too cold for them to do optimally. In a container neither needs to be a problem. Some of the herbs you can manage their size by pruning (using) them, but I wouldn't do that with dill. I don't know if you just want a little dill every now and then or if you want a lot, but if you prune the dill to limit it's height you are going to reduce the amount the plant produces and they don't really produce a lot per plant.

Some basil types can grow above 3 feet tall. Cilantr and dill also can grow quite tall if left to seed. Here is a link that might be useful: Planter that fits over railings

mint: can get up to 1 metre tall, and spread as far as the eye can see into the horizon, and beyond. coriander: 60cm tall and about 40cm wide, and it self seeds widely - I usually suggest leaving a space in the garden at least 1 metre in all directions. basil: 1 metre tall with a spread of about 30-40cm. That's what most books tell you. Frankly, I think this size plant is a dwarf. Mine get much taller than that, and at least twice as wide. thyme: gets to about 20cm tall (can get quite a bit taller. Mine is about 30cm and only 3 months old) and will spread to cover a circle about 1 metre in diameter, often more. rosemary: Mine is more than 1.5 metres tall, and at least that wide - after trimming it back by one-third recently. Judge how big the pot needs to be for yourself. Visualise 1 metre as a yard (it's actually about 39 inches). For best results, think of planting any plant upside down. If the top bit fits into the pot without being scrunched too much, that's the best size pot to get. Plants differ, of course, but it's a good idea to think of the above-ground bits, and the below-ground bits as roughly the same size if the plant is given the freedom to spread. That's why horticulturists advise watering plants in a circle measuring roughly the same as the widest parts - the 'drip line'. Of course, any potted plant will be stunted to some degree. The optimum sizes referred to above are those of mature plants in the garden. I still think only thyme will be happy in the size box you mention - using it as a pot. Even then, it could be cramped.

HJ I've had weired things happen to me too. I think your idea of a bird may be on target. I would try again, put some sort of netting across the window box that will deter the bird this time. Funny, I have a fake owl in the garden this year for the same reason. My son found the owl in someone's trash pile, brought it home and I have not had a problem with birds on my peaches or squirrels for that matter! Good luck MLCH