When it comes to growing tomatoes, there’s no shortage of advice, and some of it has been handed down for generations. Fortunately for us, there are researchers who put these time-honored tips to the test. So, which recommendations have been proven as nothing more than garden myth? Let’s take a look at the most common tomato growing myths and the science that’s really at work.
1. Adding Epsom Salts or Eggshells to the Planting Hole Prevents Blossom End Rot
This is one of the most pervasive garden myths out there. Part of the reason for this is based on the scientific truth that blossom end rot is caused by a calcium deficiency. Eggshells contain calcium, so gardeners have reasoned they would fix the calcium deficiency. The fact is, they won’t.
Why the belief in epsom salts? Good question – it’s just anecdotal. They don’t even contain any calcium. The bottom line is that they don’t do anything to offset blossom end rot.
The calcium your tomatoes need for healthy fruit is nearly always present in soil naturally. It’s uncommon for soil to be calcium deficient. So, why is blossom end rot so common? Well, the calcium is there, but it’s unable to move through the plant to the fruit.
Consistent water is what allows the plant to transport calcium from the soil to the ripening fruit. Those telltale brown spots on the bottom of your tomato are an indication that you need to adjust your watering – not your calcium levels.
Water provided through from a soaker hose or drip irrigation nearly always solves the problem of blossom end rot. That’s because the consistent delivery from those systems allows the plant to efficiently process the calcium and other nutrients in the soil.
Still not convinced? Take a soil test. It’s an easy and inexpensive way to be certain whether or not your soil is calcium deficient. It will also provide important details on your soil pH and what amendments really will improve your soil overall.
If the soil test does determine that your soil is in need of a calcium supplement, use gypsum or dolomitic lime. Those calcium-rich minerals will break down quickly to be available for your tomatoes during the growing season.
2. Epsom Salts are a Good Garden Fertilizer
Another garden myth. Epsom salts are actually magnesium sulfate. Plant growth does require magnesium for healthy growth, but it requires so many other important nutrients which epsom salts don’t provide.
Nitrogen, phosphorus and potassium are the primary nutrients required by plants, and those top three are used in various levels, depending on the stage the plant is in. For example, nitrogen is most important for healthy foliage development.
Soil is rarely deficient in magnesium. Here again, your best step is a soil test to determine what – if anything – your soil is deficient of. After all, it’s just as possible that your soil naturally contains too much of a certain nutrient or mineral – and that’s not good either. So, you don’t want to exacerbate an already existing oversupply by adding more of something.
When you do amend your soil, please consider using organic fertilizers. There are a number of reasons organic nutrients are the better choice – for soil health, plant health and environmental health. You can learn more on the facts behind fertilizer in a post I wrote last year.
As for the epsom salts, save those for the bath and easing the aches and pains earned after a long day in the garden.
3. Eggshells, Coffee Grounds & Banana Peels Will Boost Plant Health When Added to the Planting Hole
Nope. At least not anytime soon.
I get it – adding something to the planting hole can feel satisfying, like you’re going the extra mile for your plants. But the fact is, these household materials just don’t offer much immediate benefit when added to the soil. While they will break down, the nutrient availability from these items happens slowly. Considering the time involved and the other beneficial nutrients plants need anyway, you have much better options to boost the health of your plants.
Don’t focus on the planting hole. Instead, add quality amendments to the entire garden bed.
Imagine someone gives you a glass of magic Health Potion. Would you dip your finger in there or, maybe, spread it on your face to improve the health of just that part of your body? No – you’d want to make your whole body healthy by drinking the potion, so it could move through your system and improve your overall health, right?
The same is true of soil, and compost is a magic potion. The soil food web – the system within your soil – will process the nutrients found in compost and deliver them throughout your garden bed to be available to all your plants – when and how they need those nutrients.
This is why I say “Feed your soil, and let your soil feed your plants.” There are other important amendments which will benefit your overall soil health too. You can learn more on those in my post on the perfect soil recipe from last spring.
If you’re dead set on adding eggshells, banana peels or coffee grounds to the planting hole, that’s okay. Just crush or tear the larger items into pieces as small as possible to help speed up the decomposition process.
Your best solution is to add those household materials to your compost. They are great additions to the compost pile. Once they break down, the nutrients from them will be readily available for all the plants in your garden.
4. Leave the Tomato on the Vine Until Fully Ripe for Best Flavor
If you live in an area with pest pressure (and who doesn’t!), you’ll be happy to hear that this is another myth.
Are you thinking of those flavorless supermarket tomatoes? Sure, they are picked long before they are ripe, but that is not the underlying reason for their lack of flavor.
Tomatoes grown for commercial distribution have been bred – genetically engineered – for certain qualities. Size, color (consumers love a bold red), and ship-ability are all coveted qualities in the commercial tomato industry.
What about the quality of flavor? Well since it can’t be marketed in the produce section, flavor isn’t important, and it’s been unintentionally bred out of most mass-distributed tomato varieties during development for size, color and ship-ability.
In other words, that supermarket tomato doesn’t taste like a damp sponge because it was picked too early. It’s because the robust flavor of an heirloom variety was missing from the supermarket tomato genetics. This, of course, is a great reason to grow your own tomatoes. There are hundreds of varieties available to the home gardener, and they offer a wild array of flavor.
So, does timing matter at all when it comes to flavor. Absolutely, and the best time to pick is at the “breaker stage.”
Once a tomato is showing some color over about 50% of the fruit (for example, half green and half pink), it’s reached the breaker stage. At that point, the tomato fruit is already packed with everything it needs to develop full flavor.
By harvesting the fruit before it’s fully ripe, you’ll beat many pests to the punch. Picking before full ripeness also prevents splitting or cracking, which can be caused by water falling on the ripe flesh.
Allow the fruit to fully ripen at room temperature. You won’t lose any flavor, quality or nutritionally value; and you can even speed up the process by raising or lowering the storage temperature. In other words, place the breaker stage tomatoes in a warmer (85 degrees fahrenheit max) or cooler room to control the ripening pace.
Never place tomatoes – at any stage – in the refrigerator, though. Any temperature below 50 degrees fahrenheit will affect the cellular walls of the fruit and deteriorate the flavor and texture.
5. Remove Tomato Sucker Shoots to Increase Fruit Production
Yes, this too is a garden myth. Tomato plant suckers won’t detract from fruit production or fruit size. In fact, they create more opportunity for fruit. Whether or not you should keep some or all of the suckers depends more on your space limitations and support structure.
If you’re not sure how to identify a tomato sucker, look for the 45 degree angle between the plant stem and the leaf stalk. The sucker sprouts at the base of that 45 degree angle. If you allow it to grow, it will develop into another stem which will, in turn, grow new suckers of its own.
When you realize that a single sucker will grow more suckers – which will grow even more suckers – you begin to understand how tomato plants become so dense very quickly. Hopefully, that also helps you to realize that removing – or leaving – suckers is how you manage the overall size and shape of the developing plant.
Every sucker which is allowed to develop into a stem will, with enough time in the season, bear fruit. So every sucker left to grow will, effectively, double a plant’s fruit production. More fruit is the goal. However if you allow the plant to become too dense, you will restrict air movement and light to the interior of the plant, and that can hinder fruiting and foster disease.
Since determinate tomatoes grow to a certain size and set all their fruit on at once, you will have a better yield if you do not prune out any of the suckers. It’s the indeterminate tomato plant suckers that require your attention.
I tend to allow most of the suckers to remain and develop fruit. It’s one of the reasons I love what I call my “Ultimate Tomato Cages.” They offer strong support for all those fruiting branches. Later in the season, I need to allow more air flow and light into the center of my dense tomato plants, and that’s when I do remove more of the new suckers coming on.
When deciding whether or not to remove a tomato sucker from your indeterminate plant, take a few things into consideration. Do you have support available for the eventual weight of the developing branch and fruit? Will it cause overcrowding within the space? Is there enough time left in the growing season to allow fruit to set?
Be strategic and don’t be afraid to experiment. As long as you observe the results of your choice, it will be a valuable lesson for future tomato seasons.
One final word of advice: If you leave more suckers and – as a result – have a larger, denser plant than you are accustomed to growing; give thought to the nutrients you provide through the season.
A larger plant, producing more fruit will require more nutrients than you have provided for a smaller plant. For my large, indeterminate plants; I add a dose of liquid fish emulsion for a natural, quick-release nutrient boost once or twice during the season. Finding the right nutrient balance for your plants might require some trial and error too, but your plants can be your guide as long as you pay attention to the subtle signals they send throughout the season.
Links & Resources
Podcast Episode 043: Raised Bed Gardening, Pt. 2: Perfect Soil Recipe
Podcast Episode 048: The Simple Science Behind Great Gardening, with Lee Reich
Podcast Episode 066: Tomatoland: The Dirty Truth of the Tasteless Tomato, with Barry Estabrook
The Numbers on Fertilizer Labels, What They Mean