All you have to do is drive by the parking lot of any major nursery or home center this time of year. Your eye (the one that's not focused on the road) will be drawn to the hundreds of pallets of lawn-care products stacked all over the parking lot and extending like building blocks out from the sales areas. Truckloads of stuff. As my 3-year-old grandson would say, "giant, monster truckloads" of stuff.So, how much of that material do you need? What types? How many bags? When do you use it? What should you be buying now, while supplies are most plentiful? Let's start your list.Soil amendments. If you're going to garden in North Texas' black clay gumbo soils, you'll have to have help. Plants turn up their roots when they're exposed to sticky black clay. So, as with the Brussels sprouts, you're going to have to sauce it up just a little if you expect success.Organic matter is the key starting point. You can buy lots of types at the nursery. Or, you can cook up your own. You'll probably want to do both. Good flower and vegetable bed preparation begins by removing all existing vegetation and rototilling to a depth of 10 or 12 inches of topsoil.Next, layer 5 or 6 inches of different types of organic matter. I'm a huge fan of sphagnum peat moss (sold by the bale and measured in cubic feet, not sold in bags by the pound). I begin with 2 inches of sphagnum peat. Then I add 1 inch each of finely ground pine bark mulch, well-rotted compost and well-decayed manure. And then, as if all that weren't enough, I'll also include 1 inch of a relatively new product called expanded shale. It's a heated clay product that Texas A&M research has shown to be invaluable in improving clay soils. I've had great results using it. Re-till the area to blend all of that down to that same depth of 10 or 12 inches of topsoil, and you'll be off to the races.Mulches. You're going to see a dozen or more kinds of mulches in stores. Gravel, river rock, lava rock, polished glass pebbles, pine bark, hardwood bark, pine chunks, pine straw, cypress, even roll-type mulches that are placed like carpet pads across the top of the soil. The key thing to remember is that mulch is something you put on top of the bed to lessen weed growth, erosion, evaporation and splashing. Soil amendments (sometimes the same organic materials that will be marked as mulches) are worked into the soil.If you talk to 10 gardeners, you'll get that many opinions on which type of mulch is best. But, since I'm writing this all by myself, I get to go first. I very much prefer finely ground pine bark mulch, that is, nickel- and dime-sized pieces. I'm just not into fluffy, stringy mulches that are hard to rake out of the way. You can also use shredded tree leaves left over from fall or pecan hulls from a local shelling house. You have many good choices.Fertilizers. There are lots of them. You'll find large national brands as well as house brands in many retail nurseries. So, what's a gardener to choose? The best way to know what you need is to have a soil test run every couple of years. Texas A&M has a fine soil-testing laboratory, but it does take several weeks to get the tests back. Access them through a quick Web search for "Texas A&M Soil Testing Laboratory."For the meantime, assume that your soil will test high in the middle number (phosphorus). They usually do, particularly in Blackland Prairie soils. That means that you'll want to add an all-nitrogen or high-nitrogen fertilizer to almost all of the plants that you're trying to grow. Look for one where half of the nitrogen is in a quality, slow-release form. Your nurseryman will show you the details on the label.Personally, I never use weed-and-feed products. I have seen way too many trees and shrubs damaged by weedkillers that might not have been needed in the first place. Apply weedkillers as they are needed, not in concert with feedings. (This is just one guy's opinion, which doesn't necessarily guarantee that it's the only way to do business. It's just my only way.)Grass seed. People ask when they can plant bermuda from seed, and my answer is, "Once the soil warms up." That's usually mid- to late April, and May is even better. Rushing the bermuda seed runs the risk of wasting all of your effort and investment due to cold soils. And, if you're just trying to fill in some bald spots by overseeding them with bermuda, save yourself the frustration. It's difficult to loosen the soil in bare areas and then get the soil grade back to a smooth surface. You're better advised to dig plugs from your healthy bermuda and transplant them into the bare spots. Take the soil from the bare spots, and trade it back to the places where you've lifted the plugs.Neil Sperry publishes "Gardens" magazine and hosts "Texas Gardening" from 8 to 11 a.m. Sundays on WBAP AM/FM. Reach him during those hours at 800-288-9227 or 214-787-1820.