FIMBY: Don't be fooled by garden myths

This is another in our “Food in My Back Yard” series, dedicated to edible gardening.

Gardening is anecdotal in the best way: Experienced gardener passes hard-earned information about soil, microclimate or the best tomato to a less-experienced gardener.

But anecdotal gardening also can be harmful, when some by-gum-I'm-right gardener shares a hoary garden myth with a wide-eyed newbie, who takes the information as fact, without ever checking on the reality.

So April Fool's Day is a good time to look at some common myths, still floating around despite being long-disproved:

-- "Adding B1 (in liquid form) when watering-in a new plant will help prevent transplant shock." This was a common practice decades ago when I first started gardening. B1 itself does nothing to help the plant.

-- "Gravel or pottery shards at the bottom of a pot will help drainage." Another oldie, this is just wrong. Understanding why means understanding how water reacts as it travels through soil. "When water moving through a soil reaches a horizontal or vertical interface between different soil types, it stops moving." ** And creates a soggy layer.  So instead of aiding drainage, this practice makes it worse. The plant could develop root rot or drown.

-- "Crushed eggshells and chopped-up banana skins will provide calcium and potassium to the new plant." In the long run, these could help the soil, but not this year. Neither will break down soon enough to help the particular plant installed there. You're better off putting the eggshells and banana skins in your worm bin or compost pile.

-- "Crushed TUMS tablets in the soil will help prevent blossom-end rot (BER) in tomatoes." TUMS do contain calcium, but most soil is not calcium-deficient. Prevent BER by keeping your tomato garden's soil consistently and evenly irrigated. Dry/soggy cycles affect the plant's uptake of nutrients, including calcium, and that's how blossom-end rot develops, often in the first tomatoes of the year.

(Interesting tidbit I ran across while researching this: Suppose that a soil analysis shows a 10-by-10-foot planting area is calcium-deficient. It would require 760 TUMS tablets to add the necessary calcium. Hardly cost-efficient.)

-- "Pruning tomato plants guarantees a bigger harvest." Ah, this one is especially wrong in our hot summer climate. Those leaves (and stems) are  there to produce food for the plant and shade the developing fruit. Heavy pruning -- down to one stem, which I have seen locally -- actually reduces yield, and then requires some kind of external shade device to prevent sunscald on the fruit that does develop. Plus, it's a lot of work! Trimming off some bottom leaves, once the plant is 2 feet or more tall, is OK, especially if they're touching the soil. And certain tomatoes will take over the garden if allowed free rein -- looking at you, Juliet -- so I prune the lowest stems after a certain point. Also, yellowing leaves can and should be nipped off. Note: Determinate and bush (patio) tomatoes shouldn't be pruned.

-- "Droplets from overhead watering will magnify the sun and burn a plant's leaves." Nope, just doesn't happen. Certainly, in the right circumstances, moisture on leaves can promote the growth of powdery mildew and other diseases. But on a sunny day that irrigation water will evaporate. Tip: Most plants prefer to be watered at the roots, not on their leaves, anyway.

-- "Don't plant cucumbers and melons next to each other." This is only true if you want to save a particular plant's seeds, so you must avoid any cross-pollinating. But the plants themselves are fine living near their cousins, and will produce what you're expecting. One caveat: Cucumbers and melons (and squash) are all cucurbits, which means they attract similar pests -- cucumber beetles, for example. Be extra vigilant for pests if your cukes and melons are near each other.