Myths of the Gardening World

A while back, I joined a “Market Gardening Success Group” on Facebook. I’ve been listening to a lot of farming podcasts of late (Bootstrap Farmer Radio, No-Till Farmer Podcast, Farmer to Farmer, Thriving Farmer Podcast, The No-Till Market Garden Podcast), and thought it would be nice to have a place to discuss the business of farming and ask questions. And occasionally, a real gem DOES come through that is well worth knowing (like this hidden publication from the USDA. The Commercial Storage of Fruits, Vegetables, and Florist and Nursery Stock).

But for better or worse, this group takes all comers, and while, yes, everyone has to start somewhere, the hubris of people starting a business of selling vegetables when they can’t tell you what growing zone they are living in, or name a warm season vs a cool season vegetable, or anything about the type of soil they are growing in caught me a little off guard. SO many fundamentally beginning gardening questions. Not beginning MARKET gardening questions, but truly questions from people who are growing a tomato for the first time in their lives ever. And then wanting to sell it. Sigh.

So, admittedly, this post is a bit of pent up outpouring of frustration after scanning through posts from this group for the last few months. The educator in me threw in where I could, and where it was related to the business of growing, while avoiding the basic “gardening 101” questions, because you can only suggest they contact their local extension office for regional resources or visit their library for beginning gardening books so many times before you start hitting your head against a wall. I DID unfollow the group, when I finally hit the “I. JUST. CAN’T. ANYMORE” point of no return yesterday. But it got me to thinking…having gardened since 1988, and being an analytical research type person at heart, there are some myths from beginning gardeners that I really wish would die! Hopefully there will be some helpful nuggets for my readers below, interspersed with the snark and the obvious rant. Grin.

In response to “what is eating my plant and what can I do about it” questions, the two recommendations I saw over and over again were Diatomaceous Earth and Neem.

So lets start with that.

Diatomaceous Earth (DE) is not the solution to everything from Colorado potato beetles to internal parasites in your animals.

Diatomaceous Earth (DE) is made from the ground-up shells of single cell diatom fossils. It comes from sedimentary rock deposits and is composed mostly of silica. It’s essentially very fine ground glass.

This ground glass is very sharp, and highly detrimental to the respiratory systems of many insects. The idea is that it eventually pokes enough holes that it dries them out and kills them. Its good for ants, cockroaches, earwigs, pillbugs, grasshoppers, slugs/snails, fleas and bedbugs. It can be a great tool in an organic gardener’s arsenal when used correctly. It is NOT a particularly effective tool on hard shelled insects like beetles, (or if it is, I can not find any studies on it) which means its pretty useless on potato and Japanese beetles. It also doesn’t work well when wet. Which means its difficult to keep it effective in a garden setting.

I DID just recently learn that you can make a spray with it consisting of 4 tablespoons DE to one gallon of water. Spray your plants, shaking the container to keep the DE in solution. As the water dries, it leaves a fine film of DE behind that will hopefully deter the creepy crawlies that want to eat your crops, at least until the next rain. I’m trying it on my summer squash as a squash bug deterrent this year, as a “what the hell, it can’t hurt” hail Mary, as there is really no good organic control for squash bugs.

When using DE, its important to get the right kind. You need “food grade” DE, which is what has been shown by safety studies to be relatively benign around humans and pets. The other two grades, pest control and pool grade, have SERIOUS safety concerns for people if inhaled or ingested (think asbestos and heavy metal poisoning). So don’t take a look at that container of pool grade DE at your big box store and think “sweet – I can repurpose this is a cheap insect killer”. And good luck figuring out how to incorporate it onto ground that gets watered all the time to kill slugs/earwigs/pillbugs.

Neem is also not the solution to every bug and disease issue

Neem oil comes from the seeds/fruit of the tropical Neem tree (Azadirachta indica), which is native to the Indian subcontinent. Neem does not directly kill insects on the crop. Instead, it acts as an anti-feedant, repellent, and egg-laying deterrent. Some insects who ingest it, particularly when in their larval stage, starve and die within a few days (its thought that it mimics some of the insect’s hormones). Some insects, especially when full grown, seem to be relatively unaffected by it (it does not work on squash bugs either). It can also be used for fungal diseases including powdery mildew and rust. The resulting left over “neem cake” after the oil is pressed out can be used as a fertilizer.

The primary effective component in neem oil is azadirachtin (you can buy sprays where the azadirachtin is extra concentrated). Because insects must ingest neem in order for it to work, it is generally not considered dangerous to bees and other pollinators, though its a good idea to use it when they aren’t actively feeding (early morning, late evening). Its rapidly broken down in the environment, and it must be reapplied every 3 to 5 days to maintain its effectiveness.

Typical insects its effective on include aphids, caterpillars (though Bacillus thuringiensis, a bacteria that is harmless to everything that isn’t a caterpillar, would be my first choice), Colorado potato beetles (larvae stage), flea beetles, flies and fruit flies, leafhoppers, leafminers, mites, psyllids, scale, thrips and whiteflies. What I notice about this list is that all of these insects are generally quite SMALL. My guess is the effectiveness has something to do with the surface to mass ratio of the bug when ingesting neem. I.e. it has a bigger effect if you are pretty small to begin with.

If you’ve ever smelled neem (it can sometimes be found in soaps and other cosmetics) you know that it has a very distinct smell that many find disagreeable. When used on plants, neem is mildly systemic (ie its taken up by the plants). So if its applied heavily on greens, you may end up with spinach that tastes like neem. And while probably safe to eat (its used in India in tooth paste) its probably not all that appetizing.

Not all bugs are bad bugs, and you need to know the difference

This is a picture, from left to right, of an assassin bug, a squash bug, and an boxelder bug. They are all members of the order Hemiptera, or true bugs. They all have sucking mouthparts. The wings folding across their backs in an “X” shape and a long piercing strawlike mouth that is tucked against their belly when not in use is indicative of the order. Most insects in this group feed on plant juices, many being specialized to a specific type of plant.

But the assassin bug feeds on other bugs, liquifying their insides and then drinking down the resulting juices. They can be a welcome partner in your organic garden. And the boxelder bugs, while annoying in large numbers, are relatively harmless, as their primary diet is the seeds of the boxelder tree (and sometimes other maples and ash trees). The seeds are not a commercial crop and the bugs do very little damage to the tree itself.

But if you didn’t know which was which, you might indiscriminately spray an insecticide in an attempt to kill what turns out to be the good guys in your garden or waste money on an insect that wasn’t really harming your plants. And given how hard squash bugs are to kill organically, whatever you spray probably won’t work anyway.

Whitney Cranshaw’s Garden Insects of North America is a great place to start when it comes to learning the insects in your garden. It should be on the shelf of every home gardener, and certainly every market gardener.

Most garden spiders, by the way, are also good guys.

The long and the short of it is that there is no one solution to every bug or disease (and evidently no organic solution at all for squash bugs – I’ve stopped growing winter squash for market because of them. Because sometimes you just say Uncle). Practicing Integrated Pest Management (IPM), is, in my mind, kind of market farming 101. The definition of IPM, according to the University of California, is “an ecosystem-based strategy that focuses on long-term prevention of pests or their damage through a combination of techniques such as biological control, habitat manipulation, modification of cultural practices, and use of resistant varieties. Pesticides are used only after monitoring indicates they are needed, according to established guidelines, and treatments are made with the goal of removing only the target organism. Pest control materials are selected and applied in a manner that minimizes risks to human health, beneficial and nontarget organisms, and the environment.” You can’t do ANY of that unless you know what’s out there to start with.

So, pest and disease management in your market garden… Some homework required.

Moving on…..

Being No-Spray is not an option for most market gardens

You know that teenage boy who assumes that the temperature everywhere in the world is the same as the living room in which he is standing and therefore there’s no need to remember his coat when he leaves for school in January in Colorado? Some growers assume their growing conditions are EVERYONE’S growing conditions. Assuming that because they are able to practice “no spray” with their particular crops in their particular location, that means that every farmer everywhere should be able to do so. Well, that just makes me want to slap people a little bit upside the head.

As I covered in this post on organic certification, stop and think about it for a second. Spraying costs money, both in time and in materials. If growing healthy bug free produce without any sprays was easy, don’t you think EVERY GROWER, large or small, organic or not, would choose to grow that way? Of course they would.

Yes, there are some crops, in some areas, that you can manage to grow without sprays. I don’t spray my plums or apricots, and they are beautiful and bug free. Not so with my apples, pears and cherries (the Western cherry fruit fly maggot in unsprayed cherries will put you off of cherries for a LONG time). No spray sweet corn? Not unless you want to be sharing every ear with a corn earworm, at least in our area. Leafminers are ubiquitous here in spinach/chard unless you spray for them in the spring. If you hold one of the infested leaves up to the light, you can see the insect in between the layers of leaf, eating away. Kind of cool, but I don’t really want to be eating them if I can avoid it.

Western Cherry Fruit Fly Maggot – YUM.

And while we’re at it, being no-spray does NOT make you an organic grower. The USDA National Organic Standards Board (NOSB) definition of Organic, as of April 1995, is “An ecological production management system that promotes and enhances biodiversity, biological cycles and soil biological activity. It is based on minimal use of off-farm inputs and on management practices that restore, maintain and enhance ecological harmony.” So, in short, if taking care of your soil and using organic soil inputs isn’t high on your list as a grower, please don’t tout your methods as somehow superior to organic growers simply because you are avoiding all sprays. Mostly, you are probably just damned lucky that you live where you live and are able to get away with it, for now.

I’m eternally grateful that we don’t have a big issue on this farm with Colorado potato beetles or Japanese beetles or tomato diseases that tend to spread easily in high humidity environments. EVERY place has its own weed or bug that we wish we could wave a magic wand and make go away (looking at you squash bugs, bindweed & Canada thistle). Your conditions are YOUR conditions and likely unique to your own farm.

Sometimes this feels like the only answer.

And lastly…

Blossom End Rot is not necessarily solved by adding more calcium

The basic premise is that blossom end rot in tomatoes and peppers is the result of a calcium deficiency. And it is. But its not that simple. Things that can affect calcium uptake include soil pH and how you water (inconsistent watering – which is common for growers who live in parts of the country where they mostly rely on rainfall – who are these people?! – can deeply exacerbate the problem). Some tomato varieties are more prone to it than others, as I discovered myself when trialing different varieties of paste tomatoes. And its now thought that it isn’t so much caused by a calcium deficiency as the plant’s inability to transport the available calcium to where its needed. (See this article on the subject, which will make your head hurt even if you DID take basic botany/biology in college.)

Adding calcium to the soil always comes along with adding some other mineral that you may or may not need, and/or affecting your pH. So having a good soil test going in is important.

Good sources of calcium include various limes, including agricultural lime (primarily calcium carbonate – will raise pH), microna lime (like agricultural lime, but much finer, so accessible to the plants faster in the short term), dolomite lime (contains both calcium carbonate and magnesium carbonate – generally only recommended if the soil is magnesium deficient – will raise pH), gypsum (calcium sulfate – will lower pH), and oyster shell flour (contains both calcium carbonate and small amounts of phosphorus – will raise pH). Sometimes a foliar application is warranted, as calcium isn’t terribly mobile in the soil, and if your plants are showing symptoms at fruit set, soil treatment is probably not going to help. Though there is debate about how mobile calcium is when sprayed on foliage as well. Sigh.

What isn’t helpful? Telling a market grower to use crushed up eggshells in the hole when you plant. Sure, that’s fun though sometimes ineffectual advice for the home gardener. But when you have 50 tomato plants, or 500? Completely unrealistic.

So, that’s my rant for July. Timing seems about right, as we hit our mid season stride and face a month of temperatures in the high 90s. We DID sneak away for a quick overnight to the Hot Lake Springs hotel last weekend. Which was a unique experience in a lot of ways. Including peafowl!

© 2019 Miles Away Farm, where we’re miles away from knowing all we need to know about market gardening, but have probably been witness to the lifecycle of a tomato plant some 22 times in 6 different climates, which does give us a small leg up.