This week, garden myth-busting expert Robert Pavlis joined me to talk about gardening products. Robert has a background in chemistry and biochemistry and is an avid gardener as well. He owns and runs a 6-acre botanical garden packed with over 3,000 different species of plants, trees and shrubs. So, he offers some valuable insights when it comes to determining whether or not a product is necessary – or even beneficial – in the garden.
Robert has written four great garden books, including a new release – Soil Science for Gardeners. We had an interesting conversation on houseplant care several weeks ago, and I have to say, that was a hugely popular episode too. So, I had no doubt that a talk on what to buy and what to avoid would be appreciated by the joe gardener audience as well.
You might know by now that I’m a gadget geek. I’ve wasted plenty of money through the years buying products that looked like something I couldn’t live without – only to find out that the latest and greatest thing didn’t work as advertised or just wasn’t worthwhile. I don’t like to see any good gardener spend money on bad products. That’s why I’ve shared other podcasts and guides featuring some of my top picks or resources for identifying what really works.
In today’s podcast, we’re covering just a few of the products that top the list of Robert’s pet peeves of things that aren’t beneficial and, in some cases, can actually do harm. I suspect that avoiding a few of these will save you a buck or two this year.
Soil Test Kits
I often recommend that gardeners have their soil tested, and I’m certainly not alone in encouraging that step. It should be a fundamental aspect of every gardener’s approach to maintaining the health of the soil. Unfortunately, this is an often-overlooked task.
Most gardeners who do take the trouble to test the soil rely on the over-the-counter soil test kits found in retail stores. These kits include chemicals or some sort of electronic device intended to test for certain soil properties. Unfortunately, they are just not worth the money.
For one thing, inexpensive retail kits aren’t very accurate. For example, take tests designed to provide the pH of your garden soil. Robert explains that, for any pH test to be worthwhile, it needs to provide accuracy within the point scale. In other words, knowing that your soil pH is 6.0 or 7.0 isn’t helpful. You need to know that the reading is 6.8 or 7.3 for the reading to be meaningful.
That’s because pH is measured on a logarithmic scale. Each .1 changes the value ten-fold. In other words, a pH of 7 is ten times more alkaline than a pH of 6 and one hundred times more alkaline than a pH of 5. So, that point number which follows the whole number is very important, but the kits typically don’t provide that level of detail.
For any soil test, your best bet is to pick one up from your local County Extension Office. These options are only around $30, and they include all the instructions too. You’ll mail a sample to the lab and have accurate results within a couple of weeks.
Unfortunately, it can be difficult to know what to do with those results once you get them. The report will include a breakdown of nutrient levels and recommendations for which fertilizer to add to improve nutrient balance. For one thing, those recommendations are nearly always based on synthetic fertilizer products, so it can be difficult to translate that if – like me – you use only organic nutrients.
Another lesser-known challenge with soil test results is that those recommendations aren’t tailored to the home gardener. They’re based on the needs of an agricultural monoculture environment – a large area of corn, for instance.
The truth is, we don’t really know what unique nutrient levels each and every plant variety requires for optimal growth. Also, our home landscapes include a diverse array of plantings – or at least they should. So, nutrient requirements and recommendations are a little subjective.
Even if you’re just testing for a vegetable garden space, each edible variety has slightly different needs too. So, what’s the ideal balance? Clearly, this can’t be an exact science. Gardening is not a paint by numbers experience. These are the elegant mysteries of nature we’re dealing with.
This is one of the reasons, I rely on compost for soil health – rather than fertilizer. It just offers so many more benefits and nutritional balance for my soil and my plants.
What I look for most when I have my soil tested – which I do every couple of years – is to understand what nutrients my soil already has enough of. It’s also a good idea to see what the report indicates your soil is much too high in, so you can avoid adding more of whatever that nutrient is.
Our modern gardening society has been so focused on fixing problems through fertilizer that it is common for our garden soil to have an accumulation of excess nutrients. Our urban landscapes are often higher in one nutrient or another than is healthy for our plants. An accurate soil test is a great tool for identifying extremes, so you can avoid making the situation worse by buying and applying more of what the soil already doesn’t need.
Soil tests available through County Extension Offices will also provide an accurate pH reading too, but here’s a fascinating side note. The tests identify the pH of the soil you send in the sample, but plant roots are surrounded by a rhizosphere. Within that rhizosphere is a thin layer of water, along with billions of microorganisms.
The exudates released by plant roots into the soil, along with the CO2 given off by all those living microorganisms will impact the pH of that thin layer of water. In particular, the CO2 can greatly acidify the rhizosphere environment. So for example, your soil might be a pH of 6.4 but the rhizosphere is a pH of 5.2. It’s the pH of the rhizosphere which has the greatest impact on your plant health.
Just further proof that we can only control so much in our gardens. The rest is up to the natural processes at work out there.
If you browse the shelves at the local big box stores, it’s not uncommon to see products marketed as “Tomato Fertilizer” or “Rose Fertilizer.” Yet if you were to compare various brands of either, you would notice that the formulations are quite different. The “Tomato Fertilizer” products would all feature different nutrient ratios. This holds true for just about any fertilizer marketed for just one type of plant.
That’s because there is no such thing as a fertilizer unique to one kind of plant. There is no magic bullet tomato fertilizer, rose fertilizer, blueberry fertilizer, etc.
Each of the three primary nutrients does offer a specific benefit when it comes to plant development, and I shared those details in an earlier podcast. So, I recommend you check that out to better understand fertilizer ratios in general.
However – when it comes to supplemental nutrients; the needs of tomatoes, roses, etc. vary depending on the soil quality and nutrient level of their garden environment. These fertilizer products are just a marketing ploy, so you don’t need shelves of various plant-specific fertilizers.
Just become familiar with the meaning behind those ratios and the nutrient value of your soil. Then, fertilize with whatever product offers the ratio that best suits your unique situation.
Even better, rely on compost instead. I do apply a dose of Milorganite®, a non-burning, slow-release, organically-derived source of nitrogen fertilizer, once a year. Other than that, I don’t rely on fertilizer for plant health, and I don’t recommend that you do either. A yearly or twice yearly amendment of quality compost will improve your soil health in many ways – including richer nutrient value across the board.
Organic vs. Synthetic Fertilizer
Did you know that the nutrients in organic fertilizer and synthetic fertilizer are identical from a molecular standpoint, so plants can’t tell the difference. It’s how those nutrients are being made available to plant roots that matters.
Synthetic fertilizers are designed to be available immediately and taken up quickly by plant roots. That fast feed can be a benefit under some circumstances – like annual bloomers in containers. Since your goal for those plants is a short-term, big-bloom impact; a quick dose of nutrients can be just what the doctor ordered.
That said, the quick uptake in nutrients can also burn plants when you overdo it. So, follow the instructions on the package carefully.
Organic nutrients, on the other hand, are in it for the long haul. They feed the microorganisms of the soil food web, and there’s no risk of plant damage. The microorganisms produce nutrients that your plant takes up. A little more time will pass before the nutrients become available for plants, but as you continue to build the health of the soil food web, it will provide greater benefits in the short and long-term. Trust me – patience is a big virtue in the garden.
Organic nutrients also improve the tilthe or structure of your soil too. They work in concert with the soil food web to decrease compaction and increase drainage. Synthetic nutrients offer zero benefit to your soil.
Liquid organic fertilizer products like kelp extract and fish emulsions can be a good source of nutrients for your plants. Like synthetic products, these provide more readily-available nutrients, but also like synthetics, they offer less benefit.
Unlike other organic materials which have bulk and add texture, liquid fertilizers don’t add more than nutrient value. Organic materials like compost improve the aggregation and overall tilthe of soil. As mentioned earlier, that reduces soil compaction and improves drainage.
Liquid fertilizers, like fish emulsion, certainly have their place in the garden. I use fish emulsion when I want to provide heavy feeder plants with additional nitrogen. Just keep in mind that liquid products will need to be re-applied more frequently, and considering that some of them are expensive, it can add up.
Another point to bear in mind is that some fish emulsions aren’t as environmentally friendly as you would hope. Some companies catch live fish, grind them and extract the liquid to produce the end fish emulsion result. Other companies use fish scraps which are leftover from the fishing industry. The use of scraps is a smart environmental choice, and it will certainly play a role in my purchases going forward.
I’m happy to report that my favorite fish emulsion product, Neptune’s Harvest, is currently produced using fish scraps. It might take some research for you to determine whether or not your favorite brand does too.
Lots of gardeners think of bonemeal as a must-have soil amendment. It’s common practice to add some to the planting hole when placing flowering bulbs in the garden. The belief is that this organic material adds phosphate and a bit of calcium that helps flowering bulbs and is just generally a beneficial ingredient for good gardening.
The thing is that bonemeal can actually cause more harm than good. For one thing, rodents (like squirrels) are attracted to its smell, which makes it easier for them to find and raid all the flowering bulbs you worked so hard to get into the ground. If you’re adding bonemeal with those bulbs, it’s a little like ringing the dinner bell for the neighboring foragers.
Also, most native soil in North America is not deficient in phosphate or calcium, so adding more doesn’t really offer any benefit. In fact, it’s not uncommon for our urban landscapes to be too high in phosphate already – due to years of over-fertilization practices.
So, have your soil tested and pass on another purchase of bonemeal unless your soil is shown to actually have those deficiencies.
Jiffy Peat Pellets
Starting plants from seed is one of my favorite gardening activities. So when I first saw these little items on store shelves, I was intrigued. They are small, compressed peat-based pellets which are designed to expand when wet.
The premise is that you place a seed or two in each pellet, and they develop in the expanded peat-based container. Then, you can plant the seedling and container directly into the garden – no transplanting required. Handy, right?
Unfortunately, there’s a catch. The pellets are covered with a mesh to hold the peat container together. The mesh is designed to biodegrade, but that happens very slowly. It’s not uncommon to find the mesh still in the garden two years or more after they were planted.
The slow-to-break-down mesh can also hamper root development. Some roots are able to pass through it, but others begin to circle the interior of the peat container. That causes the plant to become root bound, and it can even strangle the plant’s ability to take up water and nutrients.
I’ll admit that, when I trialed these as part of my preparations for my Master Seed Starting course, I loved how convenient they are. The seedlings did very well in them too – for the first few weeks. However, I made a point of cutting away and removing the mesh before I transplanted the seedlings into a larger container to give them the additional root space they needed. Robert and I would both recommend removing the mesh before planting these into the ground too.
I’m not going to beat around this bush. I hate landscape fabric. Turns out that Robert does too.
A lot of gardeners use landscape fabric thinking it will work as it’s marketed to work – to control weeds. While this layer of material will smother weeds for a year – or two if you’re lucky, it will quickly create a bigger problem.
As the months pass, organic material and blowing soil builds up on top of the fabric. That creates two problems. First, weeds begin to germinate in those small growing spaces accumulating on the surface. Second, the build-up clogs the pores of the landscape fabric, which inhibits water from moving through it. As a result, the plants under the material can become thirsty and stressed.
We also underestimate how determined plants are. They can and will break through landscape fabric. Their roots and foliage will entwine itself into the material, and then, you really have a mess. If you’ve ever removed landscape fabric, you know it can be hard work.
When you’re shopping for soil or soil mixes, you might have seen bags touting the fact that they include mycorrhiza. What does that mean, exactly? Mycorrhiza are fungi which play an important role in nature. Are they beneficial when present in soil? Yes. Is it worthwhile to purchase them? Probably not.
Mycorrhiza are probably in your soil already. If you have extremely poor soil, they may not be present, but they won’t survive in poor soil either. You first have to improve soil health to create the environment these fungi require to live and multiply.
Mycorrhizal spores are constantly moving through the air, so once your soil is a hospitable environment, they will begin to populate it. Adding them before your soil is ready will do no good.
The fungi might benefit container plants, since those small spaces typically exist for only part of the year, but Robert points out that excess phosphate – a nutrient in most fertilizers – kills mycorrhiza.
One study tested various brands of garden products which proclaimed to contain mycorrhiza and/or other beneficial bacteria. The study found that oftentimes, the lifeforms marketed on the package weren’t actually in the product. If they were in the product, they were often dead, and dead bacteria and mycorrhiza are of no use as an additive.
The thing is that mycorrhiza – and other living microorganisms – are very susceptible to changes in temperature, so it’s highly likely that they didn’t survive the shipping to bring that product to the store. We, as consumers, have no way of knowing what’s really in that bag or if it’s even viable.
There’s no harm to using a product containing mycorrhiza, but they certainly aren’t worth spending extra money on.
Two of the most common pruning tools are the anvil pruner and the bypass pruner. What’s the difference, and do you need both?
The bypass pruner is the classic pruning option. When operated, the blade passes by a hook-shaped plate without a cutting edge. The plate is designed to provide support as the blade makes the cut.
The cleaner cut of bypass pruners is designed to reduce damage when cutting living plant material.
An anvil pruner, on the other hand, is designed with a blade on one side and a flat plate that the blade buts up against when a cut is made. This design results in a crushing cut, rather than a clean cut. That’s why anvil pruners are recommended for use on dead wood only.
Oftentimes, stores will carry pruner kits which include anvil and bypass pruners, but you just don’t need both. Bypass pruners can be used on live or dead plant growth, and they do the job very well. So, stick with bypass pruners – and pass on the anvils.
Hopefully, these insights will save you some money this season and in seasons to come. I’m a huge proponent of experimenting and not being afraid to try something new. After all, that’s one of the best ways to learn. Yet when it comes to spending your hard-earned dollar, it’s always worthwhile to take the advice of industry experts who have done the research.
You can listen in to my conversation with Robert by scrolling to the top of the page and clicking the Play icon in the green bar under the page title.
What’s the one garden gadget you’ve purchased that you feel has been one of your “top buys?” I’d love to hear your feedback in the Comments section here.
Links & Resources
joegardener Online Academy Three popular online courses on gardening fundamentals; managing pests, diseases & weeds; and seed starting!
Master Seed Starting – My newest online course teaching you how to master the art of starting your own plants from seed and seeding care!
Garden Myths: Book 1, by Robert Pavlis
Garden Myths: Book 2, by Robert Pavlis
Soil Science for Gardeners: Working with Nature to Build Soil Health, by Robert Pavlis