366-How Gardeners Can Adapt to Climate Change, with Toni Farmer 

| Podcast, Prepare

Climate change has forced food growers to adjust how they garden, and as trends toward more extreme weather continue, this will only become more true. My guest this week, organic gardener and environmental studies professor Toni Farmer, explains the steps gardeners can take to mitigate the effects that climate change has on their crops.

Toni lives in the Delaware Valley outside of Philadelphia, where she is a vegetable garden consultant and an adjunct professor. Toni and I are kindred spirits. We’re both food growers who like a nice, tidy vegetable garden, and we also like to go geeky on the science behind gardening.


Toni Farmer is a vegetable garden consultant and an adjunct professor.

Toni Farmer is a vegetable garden consultant and an adjunct professor. (Photo Courtesy of Toni Farmer)

Meet Toni Farmer

“Gardening went out of fashion with the baby boomer generation,” Toni says. “So prior to World War II, everyone had a garden. Everyone had chickens. Many people had farm animals in their yard. My grandmother did.”

When the baby boomer generation was born, society changed, she says. “It was about convenience. This is where Lunchables came in and microwaves and TV dinners and fast food. And women went into the workforce, and we really changed our relationship with food.”

Gardening is hard to learn from a book, Toni says, and is something that needs to be learned from another person. Parents and grandparents had passed it down through the generations, but that has largely ceased to be the case.

“My mom was a rare boomer,” Toni shares. “She gardened my entire life, and I was a typical teenager. I’m like, ‘What is my mom doing in the backyard? This is so stupid.’ But to all the parents out there, your children are watching.”

After Toni got married in 1992 and settled into a new home, the first thing she did was put in a garden and plant raspberries and peas. She admits she chose those crops because she didn’t know how to grow anything else. 

“I’m still obsessed with raspberries to this day,” she says. “I think it’s my favorite thing to grow.”

She recalled that when she harvested peas for the first time, her husband looked at her and said, “We’re not gonna eat that, are we?”

He thought that the grocery store did something to peas to make them edible. Toni realized just how separated from their food supply people are.

Toni continued gardening for about seven more years using conventional gardening methods — applying synthetic fertilizer and pesticides. But then she had children. She would go into the grocery store and buy organic baby food, and she had a lightbulb moment when she realized that it didn’t make sense for her to use chemicals when she grows her own food. That launched her on her organic gardening journey.

After exhausting everything she could learn on her own, she went to the University of Pennsylvania for the environmental studies program. 

“It’s applied research, meaning we’re not in the lab,” she explains. “We’re taking all this really good research that’s already been done and applying it. We’re teaching people how to use it and spreading it around so it gets used. That was an incredible experience. And then I started teaching after that.”

Toni now teaches a class called “The Future of Food” at Rowan University, and this fall will begin teaching an Integrated Management Class at Penn.

The Future of Food is an intro to agriculture or agronomy course that explains why agriculture is struggling in the face of climate change.

“Most of my students — this is funny — they take the class because they’re trying to get out of a lab science,” Toni says. “So I have a lot of business students, IT, teacher, psychology, who just don’t want to take chemistry. And Rowan allows them to take my class to check that box. So the first day of school, they have no idea what they have just stepped into.”

She warns her students that over the semester she will terrify them.

“I don’t think of myself as an alarmist, but our food system is very fragile right now, and it could break down at certain points,” Toni says. “And climate change is making that worse every day. We could talk about all the plants and crops that are in danger of completely going away, like coffee and chocolate and others that are severely threatened.”

She spends most of the semester scaring students about how their favorite foods are in jeopardy but then circles back to explain what technologies, research and people are working toward solutions.

“There’s some really cool people working in this space to fix it,” she says. “It is fixable, but we will need good policy and good cooperation across our political aisles to do that.”

 Threats to the Food Supply

There are so many things threatening our food supply, and many are in the news on a daily basis, Toni says. “The feed moves so incredibly fast, and a lot of it is painful, scary stuff. And we all become a little bit of an ostrich, myself included. ‘That thing sounds really hard, and I have no solution for that. I’m just gonna stick my head in the sand and move to the next cute cat video because that’s really fun and enjoyable.’ But I read all those articles because it’s part of my job.”

Toni talks to farmers on a regular basis, which she finds incredibly enlightening. “Even reading an article that’s a month old, things can change, or the application of that isn’t the reality for the farmer.”

She reports that farmers are experiencing drought. Rainfall is shifting, with some areas becoming much more dry and some becoming much more wet.

“How much rainfall hits a crop drastically impacts how successful it is,” she says. “So you’ve got areas of the country where the aquifers are drying up, the rivers are drying up, they can’t irrigate, they’re not getting the same rainfall. Nothing’s more stressful than coming out and seeing your corn or whatever crop that was thriving last week, and now it is wilting in the hot sun. And then on the other hand, you’ve got areas where it’s flooding, and the plants are dying.”

One farmer had hail kill his crops twice in one season.

We’re still able, for the most part, to get the food we want, miraculously, but we don’t see or feel the pain and the struggle and the stress that the people who are providing that food for us are going through. And we shouldn’t take that for granted.

“They are more stressed than ever, and there is a percentage of farmers who don’t acknowledge climate change is manmade, and that’s fine,” Toni says. “I will continue to speak with them because they will acknowledge that the weather is making them crazy. They are tearing their hair out over this.”

Degraded Soil, Damaged Ecosystems & Erosion

Degraded soil is a huge issue, according to Toni.

“The use of synthetic fertilizers for 50, 60 years now has degraded our soil and killed the soil microbiome, which is all anyone in the agriculture world wants to talk about right now,” she says.

Agricultural soil has become poorer while the average global temperature has gotten warmer, which has damaged ecosystems. Toni says natural predators don’t show up at the right time and insect pests are expanding their geographic range. 

“I have aphids already, but the ladybugs aren’t out yet,” Toni says. “I can’t rely on these bug insects to hatch and match up the way they used to any longer.”

The same unseasonably warm temperatures that cause insects to wake up at the wrong time also lead plants to bloom with disastrous timing. For example, Toni says, Georgia lost 90% of its peach crop last year because the trees blossomed out early, followed by a surprise late frost.

Erosion is an enormous issue, Toni adds. 

“We are losing topsoil and groundwater,” she says. “We’re extracting the groundwater, and then it’s eroding and flowing into our rivers and getting dumped into our oceans where it’s now salinated as salt water, and we can’t use it any longer.”

“We’re getting cloud bursts because warm air holds more water,” she continues, “And so it’s almost like a cloud running to the bathroom and doesn’t make it. Instead of a gentle rain all day long, we get these bursts.”

Too much water all at once damages crops, she points out. And on top of that, instead of climate change leading to increased temperatures on a slow, even linear pattern, “we are recognizing now that is not true. It’s wild fluctuations as the temperatures are heading up,” she says.


A ladybug seen not long after Amy started photographing her garden. This was one of the first to start showing up.

If ladybugs are not active at the same time as aphids due to climate change, they won’t provide biological pest control.
(Photo credit: Amy Prentice)


Garden to Save Money

“It’s reflected in our food prices, but the average person doesn’t understand that,” Toni says of climate change’s effect on crops. “They’re blaming Congress and politicians and anybody else.”

The war in Ukraine has contributed to higher food prices, she acknowledges, and she points to price gouging as another factor. For example, there was a bumper crop of apples last year, but that did not lead to lower prices at grocery stores.

“We may be getting to the point where not only is gardening relaxing, organic, good for you — all the long list of things — but it might actually become less expensive than buying from the store,” Toni says.

“I don’t expect we’re going to grow all our food in our backyard,” she continues. “I don’t think that at all. But it’s a really good backup plan. It’s a good way to augment your own little personal food security for your family. And also I believe it gives people a deep understanding of what farmers experience, makes us more sympathetic and wanting to learn more and get to know a local farmer, which is also a great goal for local gardeners.”

I’m so thankful I know how to grow everything that comes out of the soil. It feels empowering and comforting to grow food when you imagine a future where you don’t have access to fresh, organically grown food.


home-grown strawberries

Home-grown strawberries can be as cheap as store-bought strawberries, considering inflation. (Photo Courtesy of Toni Farmer)


Extreme Heat Halts Plant Vigor

In 2022, the Delaware Valley experienced a heat wave for weeks on end. In July, when Toni’s garden should have been exploding with tomatoes and peppers, everything had stopped growing. 

“I had never seen this before,” she says. “I didn’t understand it. All the people that follow me on social media for advice were confused, and I didn’t have answers for them.”

Then late that summer came a study out of the University of Delaware, which revealed that photosynthesis slows down rapidly at 94°. That temperature for one day won’t hurt plants, but when it lasts for 10 days, plants enter survival mode — not growth mode.

The extremely high temperature also affects plants at night, slowing their respiration. “Over 75 degrees, they start releasing a lot of water. And this creates problems,” Toni says.

“So those high temps were shocking. I hope we don’t see those again, but we’re going to need strategies to combat that.”

Three Strategies to Mitigate the Effects of Climate Change

There is nothing like soil health. 

“We went from years ago, when I was a younger gardener, it’s all about the plant, the plant, the plant, the plant. And the soil was just a medium. We didn’t even think about it,” Toni says. “You poured your water and your fertilizer in and expected things to happen.”

Now, we understand that in the soil microbiome, a teaspoon of soil contains billions of microorganisms. Tony says that overlaps with our gut microbiome. People take probiotic supplements or try to eat probiotic foods without realizing that a healthy microbiome comes from soil. 

“If you don’t have a healthy microbiome, your plants aren’t happy, your gut’s not happy,” she says. 

The soil microbiome facilitates the exchange of nutrients between plant roots and soil. When soil microorganisms die off due to drought or pesticides, cation exchange happening at the root level is diminished, and plants struggle. “They might still grow, but they’re not going to flourish,” Toni says.

She encourages gardeners to add a few shovelfuls of compost to their raised beds to get the sterile store-bought topsoil active.


A teaspoon of soil

A teaspoon of soil contains billions of microorganisms. (Photo Courtesy of Toni Farmer)



Toni is fascinated with biostimulants

“This is a whole new world opening up to us,” she says. 

Biostimulants include fulvic acid and humic acid.

Toni has watched a microscope video demonstrating what happens when biostimulants are added to soil. Before, there are soil microbes and a little movement. After, it’s like a microbe party is happening. 

“That creates a couple of really good things,” Toni says. “It allows plants to uptake nutrients better. The research suggests it allows plants to uptake water and hold onto it better, which is water conservation. And then better cation exchange — that soil ability to just exchange those ions gets ramped up.”

Toni has used PT Booster by Nature’s Wonder and Biofeed, and Arbico Organics has a suite of products. 

“Don’t use this to substitute your fertilizer. It’s used in conjunction with,” Toni notes. You can also buy bottled microbes, and add biostimulant to feed them. “And then the fertilizer for your plants can be a happy trio if you feel your soil’s damaged.”

A little Biostimilant can get you far.

“You don’t need much of it, which is beautiful,” Tony says. So they’re not super expensive products to begin with, but I only treat twice a year, and it’s a capful for a significant area of my garden. It’s not like fertilizer where you’ve got to buy it and keep applying, applying, applying.”

Biostimulants also help soil retain moisture better.


Pt Booster

Biostimulants support beneficial microbial life in soil. (Photo Courtesy of Toni Farmer)


Cut Down on Excess Heat for Happier Plants

Suspending shade cloth over food crops can knock down the heat a bit. University of Delaware studies have substantiated the effectiveness of shade cloth in giving plants relief from heat stress.

Most vegetable crops need six to eight hours of direct sunlight daily — at a minimum. So using shade cloth seems counterintuitive. The grade of shade cloth University of Delaware found to be successful was 30%. That means 70% of the UV light still makes it through. That little bit of difference in heat made a big difference in plants’ vigor.

Toni typically aims for well more than eight hours of direct sun; she decided where to plant sun-loving crops, but because of heat stress concerns, she is experimenting with growing in areas that get just the minimum amount of sun required.

Another way to cut on heat stress is by using fans.

“I don’t ever want to suggest using something that’s not sustainable and using energy, but plugging a box fan in, if you are desperate, can reduce the temperature 10 degrees or so around your plants,” Toni says. “If you’re just trying to get through the end of a heat wave, that could be a strategy for you.”


Shade cloth clipped to hoops to protect cool-season crops

Shade cloth can cut down on heat stress in plants while still allowing adequate light to pass through.


Water Conservation and Drought Management

“Not only is it good for your pocketbook and it’s good environmentally, but it’s good for your plants,” Toni says of water conservation techniques. “A lot of plants don’t like to dry out.”

Practicing good water conservation is a win for everyone: your plants, the environment and your water bill. 

“Your plants are happier because they’ve got this stable access to water all season long,” she says.

Compost and other organic material added to soil helps the sand, silt and clay hold moisture better.

Toni relies heavily on organic mulch in her garden. She starts with brown, non-glossy cardboard boxes, lays the cardboard on the ground, and adds three inches of mulch on top. The soil under the cardboard stays moist even after two weeks of drought.

She says this saves her time because she doesn’t have to constantly stand outside in a heat wave applying water, half of which is lost to evaporation. Mulch keeps soil cooler and reduces evaporation loss. 

“I rely heavily on soaker hoses. So do this now. Don’t wait until the summer, purchase a soaker hose and get it in the bed and covered with mulch before the season even starts,” she adds.

An old damaged garden hose can be repurposed as a soaker hose instead of being sent to a landfill. Tie off one end, and drill holes in the hose with a small drill bit every few inches, Toni says.


Soaker houses in Toni Farmer's garden

Toni uses soaker hoses to ensure her soil never dries out. (Photo Courtesy of Toni Farmer)


Climate Change’s Impact on Pest Management

Pests are one of the biggest challenges that we have, and gardeners can control pests in an approach that is very responsible, sustainable and ecological, or we can do it in a way that’s not so nice. Before employing control methods, we must understand what pests we’re dealing with and how climate change exacerbates pest issues. 

The winter chill that used to control pest populations — killing up to 90% of overwintering pests eggs and larvae — is no longer reliable. Where Toni lives in the Delaware Valley, she recalls sustained temperatures below 25° that lasted for weeks on end. “It doesn’t get that cold for long periods anymore, so pest populations explode,” she says.

Another climate change-driven pest issue is the desynchronization of when pests and their predators wake up in spring. If pests wake up early due to unseasonably warm weather, they will have free rein because the predators are not out yet.

And pests that used to have just one or two generations a summer may now have three or four generations before settling down to overwinter.

Toni urges gardeners to use Integrated Pest Management, or IPM. At its essence, IPM involves using the least impactful pest control necessary. For example, Toni handpicks harlequin beetles off her brassicas as a first step, and that may be all that’s needed to control the pest issue. 

When handpicking is inadequate, gardeners practicing IPM move on to biological controls, such as buying ladybugs or lacewings, and they use netting that physically excludes pests.

Toni uses pesticides only after every other control method has failed her, and she only uses organic pesticides.

“Don’t go willy-nilly killing everything because you’re going to kill beneficial insects and all kinds of other stuff and upset the ecosystem that is your microclimate,” she says.

Of all the insects out there, 99% are not harmful. They’re either beneficial or benign. So why in the world would you spray with a broad-spectrum, non-selective pesticide to kill everything when only 1% may be pests? 

Toni notes that even harmful pests are food for something else: ladybugs love to eat aphids and lacewing larvae eat flea beetles.

If you want the natural systems to manage your pests for you, you need some pest insects in your garden to attract the beneficial and predatory insects to keep everything in balance. 


Lacewing eggs

Lacewing eggs on fallen leaves. Lacewings are beneficial insects that prey on pests.


If you haven’t listened to my conversation with Toni Farmer on how gardeners can adjust to climate change, you can do so now by clicking the Play button on the green bar near the top of this post.

How have you changed your gardening practices to account for climate change? Let us know in the comments below. 

Links & Resources

Some product links in this guide are affiliate links. See full disclosure below.

Episode 195: Identifying and Controlling Garden Pests Organically

Episode 280: How to Get More Beneficial Insects in Your Garden to Manage Insect Pests Naturally

Episode 283: A Soil Chemistry Primer: How Protons and Electrons Influence Soil Moisture and Fertility

Episode 237: Ecological Gardening: Creating Beauty & Biodiversity

Episode 331: The Ecological Garden Blueprint: 10 Essential Steps That Matter Most 

joegardener Online Gardening Academy™: Popular courses on gardening fundamentals; managing pests, diseases & weeds; seed starting and more.

joegardener Online Gardening Academy Organic Vegetable Gardening: My new premium online course. The course is designed to be a comprehensive guide to starting, growing, nurturing and harvesting your favorite vegetables, no matter what you love to eat, no matter where you live, no matter your level of gardening experience.

joegardener Online Gardening Academy Master Seed Starting: Everything you need to know to start your own plants from seed — indoors and out. 

joegardener Online Gardening Academy Beginning Gardener Fundamentals: Essential principles to know to create a thriving garden.

joegardener Online Gardening Academy Growing Epic Tomatoes: Learn how to grow epic tomatoes with Joe Lamp’l and Craig LeHoullier. 

joegardener Online Gardening Academy Master Pests, Diseases & Weeds: Learn the proactive steps to take to manage pests, diseases and weeds for a more successful garden with a lot less frustration. Just $47 for lifetime access!

joegardener Online Gardening Academy Perfect Soil Recipe Master Class: Learn how to create the perfect soil environment for thriving plants.

Earthbound Expeditions: Discover South Africa with Joe Lamp’l

joegardener Newsletter

joegardener Facebook

joegardener Facebook Group

joegardener Instagram

joegardener Pinterest

joegardener Twitter

joegardenerTV YouTube

Growing a Greener World®  


Toni Farmer in Instagram: @tonifarmersgarden

Toni Farmer’s Garden Club on Facebook

Toni Farmer’s Garden on Facebook

Toni Farmer’s Garden on Pinterest

Toni Farmer’s Garden on YouTube

“The Goal Is to Become a Gardener” Video Series

FOX Weather Philly: Number one thing you should do to your garden this week

“Protecting Your Garden From Heat Stress” | University of Delaware

Timing Spring Vegetable Planting with a Changing Climate | University of Delaware

PT Booster by Nature’s Wonder


Arbico Organics 

Proven Winners ColorChoice – Our podcast episode sponsor and Brand Partner of 

Earth’s Ally – Our podcast episode sponsor and Brand Partner of 

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Greenhouse Megastore – Our podcast episode sponsor and Brand Partner of – Enter code JG10 for 10% off your first order

Disclosure: Some product links in this guide are affiliate links, which means we get a commission if you purchase. However, none of the prices of these resources have been increased to compensate us, and compensation is not an influencing factor on their inclusion here. The selection of all items featured in this post and podcast was based solely on merit and in no way influenced by any affiliate or financial incentive, or contractual relationship. At the time of this writing, Joe Lamp’l has professional relationships with the following companies who may have products included in this post and podcast: Corona Tools, Milorganite, Soil3, Greenhouse Megastore, Territorial Seed Company, Earth’s Ally, Proven Winners ColorChoice and Dramm. These companies are either Brand Partners of and/or advertise on our website. However, we receive no additional compensation from the sales or promotion of their product through this guide. The inclusion of any products mentioned within this post is entirely independent and exclusive of any relationship.

About Joe Lamp'l

Joe Lamp’l is the creator and “joe” behind joe gardener®. His lifetime passion and devotion to all things horticulture has led him to a long-time career as one of the country’s most recognized and trusted personalities in organic gardening and sustainability. That is most evident in his role as host and creator of Emmy Award-winning Growing a Greener World®, a national green-living lifestyle series on PBS currently broadcasting in its tenth season. When he’s not working in his large, raised bed vegetable garden, he’s likely planting or digging something up, or spending time with his family on their organic farm just north of Atlanta, GA.

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