Urban Gardening

Botany For Gardeners: A Beginning Botany Guide

botany for gardeners

Helpful Plant Biology and Botany Book For Gardeners and Naturalists

As the gardening season swings into full bloom, I'm reminded that it's hard to find good basic information about botany, with the breadth and depth that most naturalists and gardeners desire or need (and not too much of what they don't want). Today's post is a short one, dedicated to a book I've found quite useful in my own garden. It's also a refresher for teaching botany classes and hikes, as well as a classroom tool. The book is called "Botany for Gardeners" and it is by Brian Capon. Currently it is in its 3rd edition, which was published in 2010, which is available in paperback, hardback, or in E-book format.

The reason I am recommending this book, is that it's an essential desktop companion for those wishing to understand plants, or those needing more understanding of the inner workings of their gardens. The author does not treat you like a professional botanist, using high level botanical jargon, but he also does not shy away from taking you into the biological basis of plant growth and development. He starts with plant cells and seeds and then progresses through roots and shoots. Through this book, you will learn the basics of how plant cells and cell walls work, as well as the laying down of xylem (water) and phloem (food) cells that supply nutrients. For me it was great to relearn how roots push their way through the soil and how apical buds unfurl. You can read about how plant growth, hormones, photoperiod, and nutrients affect plants, or you can deep dive into flowers and plant reproduction.

This book is a very simple and concise look at botany in a practical way. Don't get me wrong, this isn't a "gardening-how-to" book, it's about the nuts-and-bolts of botany and plant biology. It is meant as a primer and refresher of botany (especially useful for those that may have had botany years ago and forgotten). "Botany for Gardeners" is written as a high school and adult level.  The  focus is  primarily on vascular plants, with some information on nonvascular mosses.

I've used this book for a plant taxonomy class for advanced biology students, ages 13-16. We didn't read the book from cover to cover, but I had them read sections to go along with the plant taxonomy we were learning. We especially used it during the first 1/2 of the class, which was based more on plant physiology and ecology. I would highly recommend ordering this book for your collection, whether you're leading plant-and-nature hikes or just interested in a deeper understanding of what grows in your garden.

 

Discovering Diatomaceous Earth

Diatoms_through_the_microscope

Diatoms as seen through a microscope. Note their stained glass window shapes and silica bodies (Photo: Wiki Commons).

To Use or Not to Use, That is The Question

As Spring infestations of pests, fleas, and insects begin, many homeowners are faced with how to control these critters, either in the home, garden, or even on pets. If you're like me, you'd rather stay away from chemicals all together. There are many different natural solutions out there for different organisms, but it's difficult to tell what works and what doesn't. In coming posts I'll explore some of these solutions, but I want to start with Diatomaceous earth.

Diatoms are a type of microscopic aquatic plankton or algae (2-200 micrometers in size). They are small photosynthetic plants.  We owe almost every other breath that we take to these numerous wee producers that are respiring in our lakes, rivers, and oceans. Their shells are made up of silica and calcium carbonate. In essence, they look like tiny stained glass windows.

diatom wiki

Pictures of diatoms under the microscope (Photo: Wiki Commons).

Their bodies are made like a gift box, with a top that slides over a bottom. When they reproduce, their two halves separate and then regenerate a new half. In the oceans, they are estimated to provide nearly 1/2 of all the primary food production for aquatic life! They've been around for a long time, all the way back to the Jurassic. Their glassy bodies have been floating around providing oxygen and food for millions of years. As these small organisms die, their glass bodies either sink to the bottom of the ocean or become sediment deposited on shorelines. When you look at sand under a microscope, you'll often see tiny grains of rock, but you'll also see the remains of diatoms. The main ingredient in making glass is silica, which is added in the form of sand. Guess who provided all those bits of silica? Diatoms!

Diatomaceous earth, or diatomite, is made up of the sedimentary deposit of fossilized diatoms deposited over millions of years.  They are usually whitish and abrasive feeling because of the nature of the silica, though the food grade kind may feel as soft as talc. It is very light because it has a high porosity and it is not combined with all the other heavy elements of rock and sand that are found in sedimentary sandstone.

Diatomaceous earth has been used in a variety of industrial settings, including for filtration, reinforcement of plastic, abrasion for tooth pastes, fillers for rubber and cat litter, and even stabilizing dynamite. One of its more common uses is as an insecticide.

diatomite mine in CA AlishaV flicker

Diatomite from a mine in CA (Photo: AlishaV. Flicker)

As a pesticide, diatomaceous earth must be unheated or calcified (which is often done to increase its filtration value). Calcification burns or melts the silica, reducing its efficacy. If you were to look at diatomite under a microscope, you would see startling edges. These glassy edges are sharp as razors to invertebrates, but won't hurt humans or large animals. This is why it has been touted as a natural pest control. Before you get too excited though, let's really examine what it does to control all of these "pests."

Diatomaceous earth acts as a very strong cutting abrasive on the exoskeleton of invertebrates, including bed bugs, fleas, ticks, worms, slugs, and all six and eight legged insects. It is essentially the "death of a thousand cuts." Those cuts open up the organism to dehydration and infection within 24-48 hours, causing death. The other property of diatomaceous earth is that it is absorptive. It acts to dry out and desiccate the microorganisms that are cut by its sharp edges. So, how is this bad you ask? Diatomaceous earth is a generalist. When you apply it to your garden, you are in turn, not only killing the harmful slugs, grubs, roaches, silverfish, aphids, and thrips, but you're also killing all the beneficial insect life as well. This includes earthworms, pill bugs, ants, beetles, ladybugs, beneficial caterpillars, and more. This generalist approach is detrimental to the ecosystem, though perhaps less so than most chemicals. The other down-side to diatomaceous earth is that it loses its potency once it rains and the diatoms clump together. It has to be applied during dry days without rain.

DSCF0017

Beneficial jumping spiders may be negatively impacted by diatomaceous earth (Photo: Karen McDonald).

As with all pesticides, you have to consider the ramifications of using it in your garden or around your home. Yes, diatomaceous earth is mostly harmless to humans and pets (with a few exceptions of inhaling etc., and it is a controlled substance through the USDA), and yes, it can be quite effective in killing grubs and other garden pests. However, it's a generalist and like other chemicals, it kills everything indiscriminately. On a microscale, I can only imagine the "gory movie scenes" of what really goes on in the undergrowth and below ground once it is applied. I can picture the razor like edges cutting the microinvertebrates and their slow desiccating deaths. I have my own opinions, but everything has a cost and must be weighed. What do you think? Would you use it? Have you used it?

 

Guerrilla Gardening and Seed Bombs

Weeds_in_Vacant_Lot_(5941291239)

There's a movement afoot called urban guerrilla gardening and its goal is to "green" unsightly vacant lots, sidewalks, neglected planters and run-down areas. This is done by using some stealth, seed bombs (earth truffles), and sometimes a slingshot. If you're tired of ugly urban deserts this may be the solution for you. Although it's not really time time of year to be planting it's the perfect time to be thinking about gift giving. Why not give the gift of greening with seed bombs?

...continue reading