If you’re a true gardener, you’re already dreaming of spring and digging out your gardening gear from the tool shed. Knowing there’s light at the end of the tunnel is probably what’s getting you through the long, cold winter.

Seed companies bank on the fact that in January, a gardener’s fancy lightly turns to thoughts of planting, to paraphrase Alfred Lord Tennyson; and to keep those flights of fancy alive they send you those glossy, beautifully illustrated catalogs.

Besides being fun to look at, seed catalogs are also a great place to shop, according to Vanessa Richins, horticulturalist, and Trees and Shrubs Guide at About.com.

The first big advantage they offer is the sheer number of varieties. Garden centers have to make decisions about which seeds they will stock because of the physical limitations of shelf space. Catalogs can offer many more kinds since they don’t have to worry about retail space. In fact, a number of seed catalogs also pride themselves on developing new and exciting varieties that are exclusive to them.

It’s also easier to see all of your options in catalog form as compared to a big wall of seeds. In a catalog, all of the varieties are neatly laid out on the page, which helps you make better decisions.

You can also order seeds earlier from a catalog than you can find them in gardening centers. This lets you maximize the growing cycle in your geographic area.

So, with all of that variety, how do you know what to choose? Vanessa says that once you decide what you want to plant, the next step is to realistically evaluate your growing space. “Make sure to measure out your garden to see how much room you really have to work with. Then, you just start reading the descriptions to see which ones appeal to you. For example, with tomatoes there are many different kinds — you have to decide if you want to go with the biggest tomatoes, or the most colorful, or the smallest, or the best for sauce. Many other tomatoes will offer a good combination of traits.”

And although when you’re looking through the catalog you may be tempted to order one of everything, that really isn’t the best way to go. Again, measuring your space is key. “You should make a drawing of your garden plot and measure it to see how much room you have. The catalog will often have information about how far apart the plants will need to be. Calculate how many plants you can fit in that space. Add at least 20-30 percent more to that number to account for seeds that do not germinate or seedlings that do not survive.”

If you’re a seasoned gardener, you’re probably on the hunt for the new and the different. Seed catalogs are great resource for you because they usually make sure you are aware of the newest varieties. These are often located at the front of the catalog. Otherwise, they usually will make sure to put the word “New” next to the variety name.

In spite of all of the reasons to purchase from a catalog, there are a few words of caution you should keep in mind. Vanessa says you want to pick a reputable company to ensure that the seeds you buy will bloom; so don’t be afraid to look online for customer reviews. “See if they have a germination rate available, which will tell you how many seeds to expect to germinate in each batch. Usually this is closer to 90 percent or more, but some seeds are naturally harder to germinate. Make sure to follow the seed planting instructions exactly.”

The other thing you need to be aware of is that your results will most likely vary if your soil pH, composition, or garden environments are different than those of the seed company’s test gardens. However, Vanessa says, “Reputable seed companies will test their plants and seeds in an effort to try to ensure that your results are the same or as close as possible.”

Seed catalog shopping can offer ease and variety, but just as in any retail situation, you need to know with whom you are dealing. While there are no guarantees of success, buying from a reputable merchant will stack the deck in your favor.