10 Tomato Growing Tips for a Disease Free Harvest - Melissa K. Norris

10 Tomato Growing Tips for a Disease Free Harvest

By Melissa Norris | Gardening

May 24

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Tomato growing tips for a disease free harvest, can I get an amen! Today we are talking all about growing tomatoes; specifically, how to grow healthy tomatoes and how to avoid many of the common things that plague them. Because, as the saying goes, an ounce of prevention is worth a pound of cure. And in the case of tomatoes, this is definitely true.

In fact, even as a fifth generation homesteader, tomatoes used to be a nemesis crop for me.

I live in northern Washington state, up in the foothills of the North Cascade mountain range. So, being in the Pacific Northwest, we do tend to deal with a lot of damp rainy weather, even in the summer (although for the past five years or so we’ve been experiencing a lot drier and warmer summers than normal for this area).

Still, this traditionally cool and rainy climate can make it really hard to grow tomato plants because tomatoes really don’t like to get wet. It opens them up to the fungus that can cause blight. Also, if you live in a cooler climate, your tomatoes aren’t going to be as productive. They’re definitely a warm, dry weather plant.

So a lot of the things that I’m gonna be sharing with you today are things I’ve learned by complete trial and error, and they’re the things that I wish I had known way back in the day when I was struggling.

I’m not kidding you… One year I had five tomato plants and I got ONE tomato off of those five plants, no joke. But now, thankfully this story has a happy ending.

Listen in below to the full podcast, Episode #180 10 Tomato Growing Tips – Tomato Growing Secrets for a Disease Free Harvest , of the Pioneering Today Podcast, where we don’t just inspire you, but give you the clear steps to create the homegrown garden, pantry, kitchen and life you want for your family and homestead.

We have for many years now successfully raised all of our tomato products for a family of four for the entire year off of 18 tomato plants; Tomato sauce, stewed tomatoes, salsa… all of those ways we love to preserve our tomatoes, plus eating them fresh when they’re in season, all off of those 18 plants.

I’m going to share those tips with you too so that hopefully you can get a larger, healthier, more productive harvest going forward.

10 Tomato Growing Tips for a Disease Free Harvest

Healthy, disease-free tomatoes start right at the time of planting. But don’t worry if you’ve already planted your tomatoes, you can still use some of these tips even if your plants are already in the ground.

Here are six steps to growing healthy, productive, tomato plants:

Step 1: Choose the right location

The first thing that you need to know about our tomatoes is where you’ll be planting them and what the soil is like. If your tomato plants are already in the ground, you’re probably not going to want to move them. But ideally you should plant tomatoes where they will get full sun for at least six to eight or more hours each day.

If you’re dealing with an area that gets a lot of shade and you need to plant tomatoes in a somewhat shaded spot, pick the area on your property that gets the most sun in the afternoon and later in the day, because usually that’s more of an intense sunlight than the sunlight we get first thing in the morning.

As far as soil goes, there are a lot of nutrients in the soil that will help your tomatoes too, not only to be robust and productive, but also to cut back on the diseases they’re susceptible to.

Your best bet is to get a soil test done so that you know the Ph level and all of the exact macronutrient levels of your soil. That way you’ll know if you need to amend for them or not. Soil tests are pretty inexpensive. A lot of local county extension offices will even perform them for free.

To learn more about how to test your soil, check out Episode #135 — How to Test Soil PH & Amend Soil

Step 2: Mix in some compost

No matter what your soil is like, you can’t really go wrong adding some compost to your soil. So if you’ve got some good organic compost, work some of that into the soil at the bottom of the hole at planting time.

Again, if you’ve already planted, then you can do what we call a top dressing, which simply means adding compost on top of the soil around the drip line of the plant, which is the outer edge of the leaves of the plant where the water drips off and hits the soil. Work in your top dressing wherever water is hitting the soil around the plant because it’s going to help carry all the nutrients to the root.

Step 3: Add calcium if needed

One of the most common problems people experience with tomatoes is blossom end rot. So as the tomato plant starts to mature, the fruit will start to rot from the flower (blossom) end of the tomatoes. This is also a common problem with squash plants like zucchini and winter squash. The end will turn soft and brown and Mushy, and then eventually black. That’s called blossom and rot. Usually this is a direct result of not having enough calcium.

Sometimes this happens because there’s not enough calcium in the soil. Other times there’s enough calcium present, but it’s not getting the calcium for some reason; The water’s not transporting the calcium to the plant.

Again, if you have a soil test done it, it will let you know if you have enough calcium present so that you’ll know if this a watering issue or it’s an actual lack of this calcium. So do a soil test first if at all possible, and add calcium at planting time or as a top dressing later.

The easiest, cheapest and most organic way to add calcium is to add crushed eggshells to the soil. Save your eggshells. Let them dry and then use an old coffee grinder or something to grind them up fine.

You’re basically going to pulse them into a fairly fine powder, because the smaller each particle is, the quicker it will break down and release nutrients into the soil. That’s going to help naturally add calcium to the soil without adjusting the Ph level. Typically I add about two tablespoons to 1/4 cup of crushed eggshells to each planting hole.

Another organic way to add calcium to your soil is by adding lime. However, using lime affects the overall Ph level of the soil, so I don’t recommend that it unless you know what your Ph level is. If your Ph level is good, then I wouldn’t use lime. I would use the crushed up eggshells.

Get my FREE Tomato Growing Guide- including seed saving! Click here to download


Step 4: Add Epsom Salt if needed

The other thing that you can add is Epsom salt, which actually isn’t salt at all. It’s magnesium, and magnesium will help your tomato plants draw up phosphorus, so a lot of people add a couple tablespoons to 1/4 cup of Epsom salt at the time of planting. If you’ve already put your plants in, you can use one tablespoon of Epsom salt in a gallon of water and water your plants with the mixture.

Step 5: Plant them Deep

Plant your tomatoes deep, right up to the first set of leaves to help develop a larger and stronger root system.

Step 6: Water tomato plants deep but not too often

Back on the topic of blossom end rot, the calcium levels in your soil may be just fine and you can still experience blossom end rot if you’re not watering correctly.

Tomatoes have a very large root system, and we want that root system to be really developed because that’s going to help make the plant healthy and vigorous and produce a larger harvest. So ideally you want to water them really deep just a couple of times of week because as the top of the soil starts to dry out, that forces the roots to dig down and to go deeper and to become bigger and stronger and more robust.

When you just do a little bit of watering each day you’re really just getting the top layer of the soil. Then again, if you’re watering deep but too often, that can cause the plants roots to stay wet. Both of these scenarios can cause problems like blossom end rot. So ideally, give your tomato plants about two inches of water, one to two times per week.

Ideally you want to wait until the top of the soil dries out before watering again. But you don’t want to let it dry out too much because if your plant starts to wilt then that’s going to stress it out too. So you really have to find the Goldilocks zone that’s not too wet, not too dry but just right.basket of ripe heirlom tomatoes

Step 7: Prevent the leaves from getting wet

Speaking of watering with tomatoes, the other big disease that tomatoes are really susceptible to is blight. Blight is a fungus, and it usually comes from overhead watering. It’s really hard to get rid of once it’s infected the plant, and it stays in the soil for a number of years, which can affect any plant in the night shade family, including tomatoes, potatoes, peppers and eggplants. So if you get blight, you don’t want to be planting any of those plants in the same soil for quite a long time.

Crop rotation is even more important when you’re dealing with tomatoes and things in the nightshade family simply to avoid sharing similar diseases like this.

As far as watering, try to water at the base of the plants to prevent the leaves from getting wet as this will help to prevent blight from infecting your plants. If you’re using an automatic watering system, avoid overhead sprinklers and instead opt for soaker hoses.

If you live in an area that has a lot of rain like we typically do, you might consider covering your tomatoes to keep them dry.

We made our own high tunnel out of an old metal car port kit, like the ones you might cover a vehicle or a boat with in your driveway. That’s where I plant all of our tomatoes and our peppers so that they’re protected from the rain. Since covering them six or seven years ago, I haven’t had a problem with blight.

For a full tutorial on how we set up our high tunnel, you can go and check out the video on Youtube. It’s an easy DIY project. We love it. It’s lasted us six plus years and she’s still going strong even after some 70 plus mile per hour winds.

Even if you have a large eve or an overhang on your house, you can put your tomatoes underneath that. You can also use a smaller hoop house out in the garden. Just be sure to cover it with greenhouse plastic or something that allows all of the sunlight to come through, because tomatoes do need full sun.

Step 8: Keep an eye on the color of your leaves

One of the other things to look out for is the color of the leaves your tomato plant, as different colors can signal different problems. Here are some things to look out for:

Purple leaves on tomato plants

If the leaves start to turn purple, especially on the underside of the tomato leaf, that’s a sign the plant is low on phosphorous.

So if the leaves are turning purple, or the plants seem to be a bit stunted, that’s usually a sign of a phosphorus deficiency. Really, the best thing for a phosphorus deficiency is really good compost and compost that has had fish waste in it. Wood ash will also help to add phosphorus. But most importantly, get some good organic compost and put that in and work it around the top of the soil so that it will push down and get those nutrients in as the plant is watered.

Lush, green leaves but few blossoms

If you have too much nitrogen, you’re going to get lots of really dark green, lush growth. That sucker is going to be like a jungle, but you won’t get a whole lot of blossoms, which we need, because the blossoms are what turns into tomatoes. So you’ll have a lot of lush green growth, a lot of vegetation, but you’re not going to get a huge crop.

Pale green or yellow leaves

On the other hand, if you don’t have enough nitrogen, usually the plant isn’t going to grow very well and the leaves will be pale green or they’ll even start to turn yellow. So if that’s happening, then you know that you need a little bit of a nitrogen boost.

One caveat is that too much nitrogen can burn the roots and kill the plant, which is why you hear people say to never use fresh chicken manure. It needs to be aged because fresh chicken manure is super high in nitrogen and you can burn the plants and actually kill them. So if I’m going to be applying any extra nitrogen, I will do that at the time of planting or in the beginning stages of growth, but then I don’t apply any more as we get into the mid season because I want it to turn stop growing so much vegetation and start producing blossoms and tomatoes.

Step 9: Picking the right variety and trellising tomatoes

We also need to talk about trellising tomatoes as they grow. There are a lot of varieties of tomatoes, but they are generally divided into two camps: determinate and indeterminate.

Determinate vs. indeterminate tomatoes

Determinate tomatoes are tomatoes that grow to a determined height and they do most of their production all at once. So over a week or two they’re just going to produce like crazy and then it’s pretty much done. They usually grow up to about three to four feet high.

Indeterminate tomatoes will grow all season long until you have a killing frost. I like them because I’ve got so much produce coming on from our garden from May to mid September, I actually don’t want all of my tomatoes to come on at once because I don’t have the space or the wherewithal to can an entire year’s worth of tomatoes over one or two weeks when I’m already dealing with the green beans and the cucumbers and everything else.

Side note: if you’re growing indeterminate tomatoes and you want to can them but you don’t have enough ripe tomatoes to can at any one time, as they ripen, take those bad boys off the vine and pop them in the freezer. Then when you get enough to can a batch, take them out and run them under warm water. The skins will just slip off. So there’s no need to sit and blanche and peel them tomatoes in the summer when it’s hot. You’re welcome!

Indeterminate tomato plants can grow up to six feet tall, so they have to be trellised and tied up or they’re going to fall over and break off and overrun you like nobody’s business. And those little cute circular tomato cages that you see in the gardening stores are not, I repeat, are NOT going to hold up by the end of the season. They will literally bend and break those things. At least that’s been my experience.

I’m going to be showing you the trellis system that we use in one of my upcoming Youtube videos, but it involves using wire and then a couple of metal posts. Those are really super sturdy and that’s how we create our trellising system, so make sure you’re subscribed to my Youtube channel and you will see that video as soon as it goes live.

Step 10: Prune tomato plants as they grow

The other thing with your tomato plants is to prune the indeterminate varieties as they grow. I don’t prune determinate varieties because they’re only going to grow to a predetermined height. But with the indeterminate varieties, I do prune them to promote more blossom growth, and so that the plant is putting all of its energy into producing fruit and not a ton of vegetation.

Remove any of the leaves or the branches that are down low and touching the soil, especially if you notice any disease starting to form. All of those leaves get removed because they’re just like little veins for disease to travel up. If there’s anything on the ground or in the soil that could lead to disease and a leaf is touching it, then it’s just a conduit for disease to enter the plant. So I remove any of the lower branches that are touching the soil or getting wet near the ground.

I also remove some of the sucker shoots, but not all as they do produce blossoms and tomatoes as well. But you don’t want to keep all of the sucker shoots because they’ll suck energy away from the main vine and away from the blossoms that are already forming, so be sure to prune most of them as they develop in the joints where the branches meets the stem of the plant. Here’s How to Prune Tomatoes For a Larger Harvest

For a full video tutorial on planting tomatoes, check out my Youtube video on How to Plant Tomatoes the Best Way.


About the Author

Melissa K. Norris inspires people's faith and pioneer roots with her books, podcast, and blog. Melissa lives with her husband and two children in their own little house in the big woods in the foothills of the North Cascade Mountains. When she's not wrangling chickens and cattle, you can find her stuffing Mason jars with homegrown food and playing with flour and sugar in the kitchen.

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