Growing lots of different tomatoes is a great way to beat fungal diseases as each variety deals with diseases differently. It's also a good idea to stagger plantings. Some plants are put in early in the season and others a little later. Growing lots of different tomatoes is a great way to beat fungal diseases as each variety deals with diseases differently. It's also a good idea to stagger plantings. Some plants are put in early in the season and others a little later.

Everyone knows that nothing compares to homegrown tomatoes. It’s fine to start with transplants bought from a nursery. They go into the ground around the third week of May in our Zone 6 climate, a little sooner in warmer areas.
There are huge advantages to starting from seed though. Probably the most common reason to start from seed is to grow a special variety. There are thousands of different tomatoes out there, and it’s fun to grow purple, pink, white, yellow and even red tomatoes. I start some at the end of March, and my main crop on April 1.

Once tomato seedlings sprout, they need plenty of light to keep them growing strong. Once tomato seedlings sprout, they need plenty of light to keep them growing strong.

One of the biggest mistakes for beginners is starting too early. The plants get too big before it’s time to put them in the ground.
It’s important to start off with the right kind of growing medium. Use a planting mix or seed-starting mix from your favorite nursery. Don't use garden soil or potting soil because it's too heavy.
Moisten the mix before putting it into the container. I use plastic six-packs from last year's flowers, but anything with drainage will do.
Lay the seed on the mix and cover it with more of the soil. Press down to assure good contact between the mix and the seed.
Cover the container with clear plastic and place it in a warm, bright location. You might be able to get away with a bright south-facing window, but you're better off growing under fluorescent shop lights. Hang them from chains just inches above the plants. As soon as the seeds germinate, remove the plastic. The most common reason newbies fail at seed growing is not having enough light to keep the plants growing strong and stocky.
Start fertilizing at half strength with a liquid organic fertilizer a couple of weeks after sprouting, then continue about once a week using full strength when they get a few inches tall.
The plants should be hardened off before going out into the garden. It’s just a process of getting them ready for the unpredictable spring weather. Take them outside for an hour at first and gradually increase the time outdoors over a week until they spend a night or two under the stars. Now the plants will be able to hit the ground running.

'Cherokee Purple' is a popular heirloom variety which produces tasty, dark meaty tomatoes. Even though this variety is popular enough to be found as a transplant at the garden center, there are thousands of other varieties to experment with in the garden. 'Cherokee Purple' is a popular heirloom variety which produces tasty, dark meaty tomatoes. Even though this variety is popular enough to be found as a transplant at the garden center, there are thousands of other varieties to experiment with in the garden.

Tomatoes are susceptible to fungal diseases, something most gardeners will have to deal with at one time or another. A cool, wet spring creates the perfect environment for the disease.
One thing that helps tomatoes thrive is warming up the garden soil. One way to do that is to cover the bed with black landscape fabric a week or two before planting. Another trick is to use a product called Wall-O-Water. It's a free-standing plant protector filled with water. Put these out in advance of planting to heat up the soil and also create an individual greenhouse for each seedling.

Planting Outside

The first thing to do when planting is to immediately add a layer of mulch. This stops the soil-borne spores of early blight and septoria leaf spot from splashing up on the bottom leaves. Both diseases usually enter the plant's system from those bottom leaves, turning them yellow and working its way up the plant. They usually don't kill the plant but can dramatically reduce production. I like to remove the bottom leaves too, making it harder for the spores to reach the plant.

Tomatoes will thrive when the planting hole is filled with compost; the soil amendment gives the plants everything they need for the season. When plants are growing strong, they fight off pests and diseases better.

Spacing

Give the plants plenty of space, at least 3 feet for full-sized, vining varieties. They also need support in the form of staking or caging. Don't bother with a little 3-foot-tall cage seen at some stores; the tomato will outgrow it by June. In my garden, each plant is surrounded by a 5-foot cage made of concrete reinforcing wire. It can be found at hardware stores and is available in rolls.

Mine are cut in 5-foot lengths with lineman's pliers and are then made into the cylindrical cage. They are put in place the day the tomatoes are planted, with the cage attached to a stake pounded into the ground. The stake stops the cage from toppling at the end of the season when the tomato plants have become huge and are flopping over the top.

If staking is for you, just be sure to get into the garden every week or so, prune the plant to one central leader and keep tying the vine to the stake as it grows. If you miss a week, you'll be wrestling with an unwieldy rampant vine or two.

Succession planting

The No. 1 thing I do to prevent fungal diseases is succession planting. I learned about it by accident through a variety called ‘Sungold.' It's my wife's favorite tomato, which makes it crucial to the garden. The plant produces loads of extremely sweet, orange cherry tomatoes.

One year, I was going to be picking on June 15 and was bragging about my early harvest to my garden friends. Mother Nature taught me a lesson by dropping a huge black cherry tree on my three ‘Sungolds' during a summer thunderstorm. You would have thought a baby was trapped under there, as I frantically cut away at the tree with my chainsaw. It was all for naught, though, as the plants couldn't be saved.

I had two leftovers in the greenhouse planted in 6-inch pots, and even though they looked a little leggy and tired, those ‘Sungold' plants loved the warm soil and air temperatures. I had never planted that late before, and at the end of the season my main crop, planted May 15, was succumbing to fungal diseases. The two leftovers had no signs of disease. The plants all had the same weather from June 15 on, but the leftovers were snug and warm in the greenhouse early on.

Planting everything the same day is a way of putting all your eggs in one basket. Now I stagger the plantings. Some tomatoes go in May 20, then more on May 30 and so on, all the way to July 4. The last planting is something like ‘Early Girl' or a cherry tomato like ‘Sungold'; both will put on tomatoes quickly and will be ready to harvest at the end of the season.

That valuable lesson of succession planting has been expanded in my garden to most crops, including peppers, cucumbers, cool-weather crops and more. It means that some of these plants are growing off the cycle of certain pests and diseases, which can make all the difference in the world.

Disease control

If the plants show signs of one of the early diseases, Serenade is a great organic fungicide that works as a biological control. It stops the fungal spores from reproducing and is safe for the environment.

Another tip is to grow lots of types of tomatoes, as each one reacts differently to diseases.

There's one disease called late blight that is fatal to tomatoes. It's not that common but hit Western Pennsylvania hard about eight years ago. Late blight often starts at the top of the plant; stems and fruit will have brownish, black lesions on them. There's no cure, but before plants are removed from the garden, be sure to have the disease properly diagnosed. Send a picture to me or your local nursery. Don't bring any plants to the garden center; this disease can spread fast. If it's late blight, the plants need to be bagged or burned.

Whether it's six tomato plants next to the garage or a field of vines, every gardener knows there's nothing that can compare to a homegrown fruit enjoyed warm, right from the plant.

Here's a fun story about a young family starting plants from seed.

Doug Oster is editor of Everybody Gardens, a website operated by 535Media, LLC. Reach him at 412-965-3278 or doster@535mediallc.com. See other stories, videos, blogs, tips and more at everybodygardens.com.