Raising big, juicy tomatoes anywhere from Iowa to Florida is easy! I'm going to give you the secrets to growing 7' tall tomato plants like you see on the right that are loaded with tomatoes all season long! There is a lot of information here so take your time.
It starts with the soil
Whether or not you provide rich, loose soil for your plants will be the deciding factor if you are successful or not. If you haven't visited the Garden Soil page yet, you need to start there and then come back. You can purchase the highest quality seed or the healthiest tomato plants but if you put them in compacted soil that has little or no nutrients, the plants will fail. Guaranteed! You can do things immediately, the first year to provide the soil your plants need and then build your soil every year.
Pick your garden spot and prepare the soil
If this is your first year for a garden, raising tomatoes requires a lot of sunshine so you'll need to pick a spot that gets a minimum of 6 to 8 hours of sun every day. The more the better. It should also be an area that has good drainage. Don't plant them in a low spot that has standing water after heavy rains.
It's best to prepare the area in the fall but you can do it in the spring. After the frost is out of the ground and it has dried out enough to work, you can mark off your spot. Assuming it is a grassy spot, you need to remove the sod. This can be done with a shovel or you can use a tiller to shallow till the area and then rake out the clumps of grass before tilling it deep. For your first year, you can rent or borrow a tiller and then decide later if you need to buy one. Word of caution, DON'T till your garden when it's too wet. If you do, you'll have big, hard clumps of soil that will cause all kinds of problems. When you're finished, your soil should be loose and relatively free of large lumps. You can build your soil organically over time but for your first year you'll need to add some compost and till that in. Most county land fills usually have large piles of it that you can get or you can purchase bags of compost at most retail garden centers.
After you've prepared your soil, you need to test it for the PH level (alkaline, acidic or neutral) and fertility (Nitrogen, Phosphorus and Potassium). You can purchase a pH Soil Tester or you can take samples of soil to your county extension office and they will test it and give you a full report with recommendations. Tomatoes prefer a PH range of 6.0 - 7.0 but if you live in an area that has highly acidic or alkaline soil, you can amend it but you should consult a reputable garden center. Your other option is to raise your tomato plants in large pots using a quality potting soil like Miracle Grow.
Concerning fertilization, tomatoes need more phosphorus than nitrogen. Too much nitrogen will cause them to grow heavy in vegetation with few blooms. To get started, you can purchase fertilizer that's specifically formulated for tomatoes at most garden centers. After you build and sustain your soil with plenty of organic material, you won't need to worry about it. I fertilize my tomato plants once when I plant them to help the roots get a quick start but nothing the rest of the season. The tomato plant you see in the photo was taken in August of this year (2012).
Planting your Tomato Plants
After the danger of frost is past and you've prepared your soil, you're ready to put your plants in the garden. But make certain the weather has stabilized in your area. If you're at the average frost date, check the ten day forecast before you plant. If you purchase tomato plants from a nursery or garden center, make sure they're healthy. They should be nice and green with no yellow leaves or leaves falling off. You should also look for good stocky plants with a strong, thick stem not tall and leggy. For a few calm, sunny days prior to that, set them outside for a few hours to harden them to the outside conditions. Even though you harden them, your plants still show some signs of transplant shock, especially if the soil temperature is cooler than normal. Don't worry, in a week or so they'll look good and healthy. I found that spraying the foliage with a fish emulsion will help them come back from transplant shock quickly.
When you plant them in the ground, plant them deep. You can plant them leaving only the top 4 or 5 inches above ground. The advantages of planting them deep are that the entire length of the stem that is in the ground will grow roots and they will remain cooler and retain moisture in those hot, dry periods. If you have plants that are long and spindly, don't worry. You can dig a long trench and gently bend up the last 6" and bury the stem. Just remember to hand pull any weeds instead of using a hoe around your plants. At this time you can apply a high phosphorus fertilizer and water well. Also, spread a thick layer of some organic material (grass clippings, straw, etc.) around the base of the plant to retain moisture. If you have any disease pathogens in your soil, it also keeps muddy water from splashing up on the plant which can start the disease spreading up the plant.
Springtime in Iowa means high winds so I always protect my plants with coffee cans that have both ends removed. I just put them over the plants and push them down a little. They do a great job of protecting the tender vegetation on the plants. When the stems have thickened and they've out grown the cans, take them off. I need to make a point about spacing. I plant my tomatoes 5' - 6' apart. Why so far apart? You'll be surprised how the indeterminate plants spread and the 5' spacing allows good air circulation (see photo) around the plants which is important to help avoid moisture on the plants which can develop disease. See Common Garden Diseases and Preventions for information on tomato blight.
Caring for your Tomato Plants
Raising tomatoes does require your attention throughout the growing season. This season I had a tremendous tomato crop, 761 tomatoes from six plants. However, even with the hot, dry weather, we had plenty of humidity which is a perfect environment for fungal diseases. I always stay ahead of disease no matter the weather by spraying them with a fungicide often. Some rainy weeks I spray 2 or 3 times.
Here in Iowa, the #1 problem with tomato plants is disease. The springs are usually wet and the summers are humid which provides perfect conditions for fungus disease. See Common Garden Diseases and Preventions. Early and late tomato blight can drastically reduce your crop. Tomato blight starts with black spots on the
bottom leaves and stem and the 
leaves will shrivel up and turn brown. The black spots are spores and when they are disturbed, they will release thousands of spores that will spread up the entire plant. If unchecked, it can eventually kill the plant. There are excellent applications for blight that you can purchase from garden stores. I have found Daconil to be very effective and you can purchase it at most retail garden centers. Just remember, fungicides work well but they don't work at all if you don't apply them in a timely manner. Start applying before the disease appears and continue to apply at regular intervals according to the directions and after EVERY rain. In some rainy weeks, I've had to spray 2 or 3 times. Remember, fungal disease develops and spreads VERY rapidly (overnight) so you can't let it get a foothold. Also, when you purchase your seed or plants, look for disease resistant varieties that have initials such a VFN or VFFN in the description. The photo at right is one of my Big Beef VFFNT tomato plants from this season (2012). The picture was taken in August and, as you can see, the plant is disease free thanks to disease prevention.
Of course when the weather turns hot and dry, you need to provide water to your plants. If your plants grow over 7' tall and loaded with tomatoes, they require a lot of moisture. Normally, 1" of water per week is sufficient but when we had extended periods of 95 - 100 degree temps, I watered my plants twice a week. When watering, always use your hose without a spray nozzle and at low pressure and water only at the base of the plant, never get the foliage wet.
Concerning pests, tomato plants don't seem to have many problems in my part of the country. I personally have never experienced any problems with cutworms but I know they are a very destructive problem in certain areas. Cutworms will chew around the plant stem at or just above ground level at night so when you come out in the morning, your tomato plant is laying on the ground. Fortunately, there's an easy solution. Dig slightly below the surface of the ground around the stems of your plants and take some aluminum foil and wrap it around the stem. I'm sure there are pesticides that will take care of them but the foil is a good method that won't hurt beneficial insects.
Last summer, I discovered a couple of tomato horn worms on my plants. One was about 6" long! They match perfectly with the green color of the tomato plants so they're very difficult to see. They do nibble a bit on green tomatoes but the number of ones that had damage was so minimal, I didn't do anything. Try not to ever use pesticides, when you spray it gets on the blossoms which can kill bees.
As your plants grow, gently place the limbs through the wire cages so they will be supported all the way to the top. Be careful to not scrape or cause a wound that would invite insects and bacterial viruses. Keep the area weeded and inspect your plants regularly for evidence of problems. As you get toward the end of the season, you can pinch off any new growth and blossoms so the remaining tomatoes on the vine will ripen before the first frost.
About pruning tomato plants
Many tomato gardeners believe that there are benefits to pruning the extra growth or "suckers" from their plants. It involves pinching or cutting off the new branches that grow in the "V" between a main stem and branch on the plant.
The theory behind it is that the plant will produce bigger tomatoes, the leaves of the plant will get more sunlight and the plant will air dry faster thereby not holding as much moisture that can cause fungus disease.
My experience and opinion is this. I read about pruning tomato plants and decided to try it many years ago. I gave up on it after about a week, when common sense hit me, for the following reasons.
Every time I pinched off one of those new growths, I would wonder how many tomatoes I was losing. I also thought about those new branches growing being a natural botanical process for tomato plants so why cut them off. The other thing concerns disease. Bacterial and virus diseases can enter the plant through an open wound so every time you make a cut to remove a sucker, you're inviting disease. Finally, I have a large yard and garden so I have enough things to do without walking through my tomato plants every day cutting off suckers and, besides, I get an average of over 120 big tomatoes from each plant and I'm very happy with that (don't fix it if it ain't broke).
The bottom line here is that I can't prove or disprove the benefits of pruning so you can do some research and decide for yourself.
Go to Tomato Varieties for information on different types of tomatoes you can grow, Starting Tomatoes from Seed for step-by-step tips with photos on how to start your own tomato plants from seed and Tomato Cages to learn how you can make your own cages and save $$$.
Don't forget to visit the Garden Photos page if you want to see how my plants did this season. You can also visit the below site to see this season's results. You'll find this website is very informative for growing tomatoes. http://www.tomatoville.com/album.php?albumid=114
