Here's my take on these questions .... if anything isn't clear, or you disagree, lemme know! I love talking food!
What is risotto?Risotto is as much a rice cooking technique as it is a recipe or item. Classic risotto uses slowly incorporated hot liquid to dissolve the rice starch and create a very creamy sauce, at the same time cooking the rice. It is Italian in origin and calls for either arborio or carnarolli rice, both of which are from Italy, but quite available in the US - at least in larger cities or from national chains. There is no substitute for a true imported Italian rice. Honest and no fooling ... don't even bother to try to find a substitute for those two types of rice; it doesn't exist. Spanish paella is a close cousin. Risotto can be a side dish or an entree, can be plain or very fancy. A mainstay in Northern Italy, it is pretty much a macaroni exchange - the South does macaroni, the North does risotto. A random Google search for "risotto" turned up this pretty good treatise on it.
http://www.arborfood.com/dining-in/gourmet-details/risotto.shtmlWhat can be substituted for thyme and cummim?I'm not sure about cumin, but oregano is very close to thyme in both taste and botanical terms.
I assume cilantro is like parsley.They're similar only in appearance. The taste is dramatically different. You can replace parsley with cilantro (also called coriander) or vice versa, but the taste of the finished dish will be dramatically different. Taste them side by side and then decide.
Do you all raise your own herbs and spices? Where do you get seeds?I can't speak for anyone but myself. We grow Italian parsley and sweet basil every year (both are annuals) and grow it from plants we buy at a nursery. We have an oregano patch (a perennial) too. In recent years, fresh herbs have been easily obtainable at our local supermarkets, so there's little need to grow herbs we don't use all that often (being Italian, parsley, basil, and oregano are much like staples for us.) We also have fig tree we planted last year ... but that's not really an herb. :)
How big of containers do you need?We grow ours in our flower beds, not in pots.
If you don't have wine, do you sbstitute something for it?If you mean wine with a meal, we usually have it every night. On nights we don't, we'll drink Pellegrino water (our local BJ's and Costco have it at a reasonable cost per case). If you mean wine for cooking, there are some opportunities to substitute, but the rules vary widely, so I'd need to know what you're making to know if wine can be substituted and with what. Common items to use in place of wine would be vinegar and citrus juices. But again, you have to be careful. They work in some cases and are awful in others.
Are lemon and lime juice interchangeable for some things?Generally .... yes. The taste is different, to be sure, but I know I often use one where the other is really called for. It changes the flavor for a nice change of pace while leaving the rest of the dish pretty much intact. Think of orange juice too ... or even grapefruit juice. Neither is tart, however, so think before ya squeeze! :)
I don't have olive oil, can I use vegetable oil? Do I add something to the other oil?As a general statement regarding substitution ... yes .... but the flavor of olive oil is in many ways why its used. It is, IMO, delicious and without substitute ... but that's a statement of preference, not of fact. As a statement about adding flavors ... be careful. Oil, while safe on its own, is not a safe medium in which to infuse flavors. Commercially infused oils are one thing. Home infused oils are quite another. Depending on what you're putting in, you could find you've also grown botulism in it! Herb infusions are the most dangerous. Now, those scary words aside, if you plan to use the oil in a short period of time, there's virtually no danger (think of oil and vinegar salad dressings with herbs added ... it'll keep a week or two with no problem. It is the longer infusions that are the issue ... a few weeks to months on the shelf. Not safe, IMHO.
I have to ask why you don't have olive oil? Cost? Availability? Taste? Olive oil, as oils go, is one of the best for you, in health terms. True, it is still an oil - fat - but it is a very healthy fat once you get past the notion of it being a fat. If cost is an issue, try a blend of olive oil and vegetable oil. Or try a light olive oil. This could also be a way around the taste, if that's the issue. Olive oils (and other specialty oils, for that matter) are in some ways like wine or coffee or tea .... they vary a lot in taste, even though they're all olive oils. Light. Dark. Fruity. Acidic. Etc. Etc. Etc.
I hate ginger root, are other spices somewhat interchangeable?I have to defer to others here. Asian cooking isn't my long suit.