A Gardener’s Primer to Cold Hardiness, Part 2

Last week I discussed the mechanics of how cold hardy plants can survive temperatures far below freezing. Today we’ll consider the practical implications of this phenomenon and what, if anything, you can do to help your plants through cold snaps.

What happens when temperatures change at unusually high rates?

Remember, supercooling occurs when temperatures drop slowly, allowing water to leave living cells and freeze in the dead spaces between cells. When rates drop quickly, which can happen on sunny winter days once the sun goes down, water can freeze inside the cells before it has time to migrate into the extracellular space.… Continue reading this article “A Gardener’s Primer to Cold Hardiness, Part 2”

A Gardener’s Primer to Cold Hardiness, Part 1

With record low temperatures in some parts of the country, gardeners are understandably worried about the ability of their perennial and woody plants to survive the cold. What today’s post will do is give you some context for understanding how plants can survive temperatures far below freezing.

Why ice floats and how this damages cells

Everyone knows that ice floats, whether it’s an iceberg in the ocean or cubes in your favorite chilled beverage. Ice is lighter than water because its molecular structure is different: there is more space between water molecules in ice.… Continue reading this article “A Gardener’s Primer to Cold Hardiness, Part 1”

Compost in Seed Starting Mix: Recipe for Success….or Failure?

A recent question posted to the Garden Professors blog Facebook group (a place where you can join and join in conversation of garden science) asked about the potential for compost added to seed starting media to cause failure in germination.  It is a good question, and one that seems to have several different camps – from garden hero author folks swearing by it in their (non-peer reviewed) books, to fact sheets saying it isn’t a good idea.… Continue reading this article “Compost in Seed Starting Mix: Recipe for Success….or Failure?”

Understanding mysteries of plant diseases

(Post 1 of 3 in this blog series)

Gardeners, especially those new to gardening may find they have a “black thumb.” Plants die for no reason! “Oh well chuck it in the greenwaste recycling can and start again.” Or… “Oh I can’t grow cyclamens!… They always die in my garden for some reason.” For many gardeners it is mysterious why some plants fail to thrive or die suddenly. Plant disease processes are complicated, and it requires some knowledge of botany (anatomy and physiology), genetics, and microbiology to really understand what is happening.… Continue reading this article “Understanding mysteries of plant diseases”

Your New Year’s resolution : No “alternative facts” or “fake news” in 2019!

Welcome to 2019! In keeping with the tradition of a new year, I’m hoping you will join me in resolving to promote good gardening science among your friends, relatives, colleagues, and customers. One of the most important tools you’ll need is a collection of resources that are not only science-based, but are relevant to gardens and landscapes (not agricultural production). With that in mind, here’s my list of authors and institutions who are credible resources.

First off, of course, I’ll have to start with the Garden Professor faculty.… Continue reading this article “Your New Year’s resolution : No “alternative facts” or “fake news” in 2019!”

Tuning up for Pruning Up–Care, Maintenance and Utilization of Hand Pruning Tools

A. J. Downer

Fall is passing into winter and the bare sticks in my deciduous fruit orchard are calling to my annual fruit tree pruning chores.  I can prune my entire orchard with very few tools: a good pair of bypass clippers, a similar set of loppers

(optional) and a high quality “razor” or “tri edge” saw.  Most hand tools require some maintenance especially the clippers and loppers.   Clippers are easily sharpened but modern saw blades can not be sharpened by gardeners.… Continue reading this article “Tuning up for Pruning Up–Care, Maintenance and Utilization of Hand Pruning Tools”

The Myth, the Legend, the Parasite: Romance, Lore, and Science beneath the Mistletoe

As we hurdle ever closer to the holidays and the end of the year, there’s lots of plants we could talk about – amaryllis, poinsettias (and the abuse thereof with glitter and paint), whether or not your cactus celebrates Thanksgiving, Christmas, Easter or is agnostic, and on and on.  Each of these plants have an interesting history and connection to the holidays, but today we’re going to be a little more naughty…but nice.  We’re going to talk about mistletoe.… Continue reading this article “The Myth, the Legend, the Parasite: Romance, Lore, and Science beneath the Mistletoe”

What’s wrong with my plant? You’re not going to find pat answers.

As many of you know, the Garden Professors host a Facebook group dedicated to the discussion of science-based practices for gardens and landscapes. (Side note – if you haven’t joined us please do!) Recently we’ve had a spate of “what’s wrong with my plant” posts, usually focusing on some leaf issue and little other information. And far too often an eager group member will jump in with a fertilizer recommendation.  So today’s blog post has two objectives: explaining why you can’t reliably diagnose problems from a picture of suffering leaves and why blanket fertilizer recommendations should be avoided.… Continue reading this article “What’s wrong with my plant? You’re not going to find pat answers.”

“Fun-guy” in your Mulch

By Jim Downer

As many avid GP readers are aware, mulches are a common horticultural tool that help gardeners maintain soil moisture, nutrient content, weed suppression and assist in disease prevention.  The best mulch is made from chipped tree trimmings wastes and has a large wood content.  Coarse “arborist chips” mulch is fast becoming one of the most frequently sought after mulches for residential landscapes.  It is very effective and contributes to significant soil improvements over time. … Continue reading this article ““Fun-guy” in your Mulch”

Thanksgiving: A celebration of the native plants and indigenous crops that grace the table

Native vs. non-native – that a subject that is brought up frequently on our forums and one we have to discuss at length.  However, I thought I’d take it from a different direction this week, a little diversion if you will, seeing as we are just a week away from our American celebration of Thanksgiving that centers around food – much of it native to the United States.

It is a holiday that is quintessentially American (or North American, since our Canadian friends also have their own Thanksgiving).… Continue reading this article “Thanksgiving: A celebration of the native plants and indigenous crops that grace the table”