Looking for a detailed guide about how to grow organic peaches in the southeast? This article will provide evidence-based solutions provided by two of the world’s top peach scientists to improve your chances of growing peaches successfully using organic methods.
This is one of our longer articles. We’d encourage you to read the whole thing to gain a thorough understanding of the subject matter, but if you’d like to skip right to a particular section of interest, here is a table of contents:
I. Introduction: How this article came to be (and our organic peach growing success)
II. Interview with Clemson University’s Drs. Guido Schnabel and Juan Carlos Melgar
III. Key takeaways: a printable quick guide to growing organic peaches in the southeastern US
If you’re trying to find out how to grow organic peaches in the southeast, there are three things you should know right up front:
- Yes, it’s technically possible to grow organic peaches here.
- No, it isn’t easy.
- If anyone can tell you how to do it, it’s two of the world’s top peach scientists: Clemson University’s Dr. Guido Schnabel and Dr. Juan Carlos Melgar
Thankfully, both scientists graciously agreed to be interviewed for this article. Even more graciously, they continued to stay on the Zoom meeting answering more of my peach questions way beyond the time I’d estimated the meeting would take.
Feeling peachy: how this article came to be
Background: we have two peach trees in our small food forest; one of them is ~12 years old and the other is ~8. Other than boosting soil fertility with mulches and old duck house bedding plus pruning each year, we haven’t done much to protect or ensure our peach crops. As such, our results have been less than stellar…
A couple of years, no fruit has set because of late freezes. A couple of years, fruit has set and produced a small yield. Some years, every fruit has been lost to pest insects. This despite us having a high degree of plant biodiversity and a huge population of predatory insects constantly on patrol.
Video: a quick look at part of our food forest and duck habitat:
*video may not play if you run ad blocker software
In fact, relative to other fruit species we grow, our peach trees yield so little fruit that we’d resolved to take them out and replace them with something easier to grow organically that would produce a reliable yield each year.
However, this year The Tyrant and I knew our baby would be eating his first solid foods come summertime, so we wanted to have organic peaches on the menu for him. Thus, we ordered Surround WP, an OMRI-listed product approved for use by certified organic farmers.
In case you’ve never heard of it before, Surround is made of kaolin clay, aka kaolinite, a silicate mineral found in clay soils around the world (including here in the southeast). Surround is applied as a foliar spray, coating the young peach fruit and leaves.
Rather than acting as a biocide, the crystalline structure of kaolin clay repels, irritates, and disorients pest insects. It also helps prevent fungal spores from propagating and the white film reduces heat stress in trees on hot summer days.
I dutifully applied Surround on our peach trees at least once per week starting shortly after fruit set in March. (More frequently if we had heavy rains.)
Come July, that investment paid off…
We had — by far — the largest peach crop we’ve ever experienced. Even after stuffing ourselves with peaches daily (and sharing quite a few with Baby Sebastian), we were still slicing and freezing 5-10 pounds of peaches each day and quickly running out of freezer space.
View this post on Instagram
Garden-to-baby eating. Sebastian enjoying baby-led weaning with fresh organic peaches from his backyard. Other favorites include roasted pumpkin with turmeric, blueberries, any cane berry, strawberries, calamondin oranges, scrambled duck eggs… well, pretty much anything we’re eating and offer him. It seems unlikely that this fella is going to be a picky eater. #gardentobaby #babyledweaning #parenting
Granted, the majority of our peaches would not pass muster in a commercial operation since consumers want picture-perfect, unblemished fruit. However, we were thrilled. And curious…
Who is the top peach expert?
If we actually knew what we were doing, would it be possible to consistently grow organic peaches here in the southeast, we wondered? I reached out to two friends: Ryan Merck (Senior Farm Certification Specialist at CCOF, formerly at Clemson DPI) and Dr. Meg Staton at University of Tennessee (Entomologist & Plant Pathologist who got her PhD from Clemson).
“Who is the top peach expert I need to talk to about this?” I asked them. Both recommended I start with Dr. Schnabel at nearby Clemson University.
Dr. Schnabel (a plant pathologist focused on peaches and other stone fruit) agreed to an interview and looped in his partner, Dr. Juan Carlos Melgar, a pomologist. Together, they’re like the Batman and Robin of peaches, helping farmers throughout our state and region successfully grow local peaches and keep their farms profitable — and keep bad guys away (pests & diseases).
The information provided below about growing organic peaches in the southeast is based on excerpts from my interview with these two very brilliant, generous individuals.
II. Highlights from interview with Clemson University’s Drs. Schnabel and Melgar
QUESTION 1. There are some fruit species that can be grown in the hot, humid southeast with relative ease – e.g. they don’t have much pest and disease pressure, nor do they require much in the way of inputs (fertilizer, irrigation, etc). So let’s go ahead and address these common questions from backyard growers/home orchardists: “is it easy to grow peaches in the southeast?” and similarly “is it easy to grow peaches ORGANICALLY in the southeast?”
Dr. Schnabel: From a disease and pest-management standpoint, it is very challenging to grow peaches in the southeast because the environment is highly conducive to pest and disease development. If a homeowner wanted to grow peaches, that would be very hard to do because homeowners usually are reluctant to spray anything. And just using cultural methods [non-chemical agricultural practices] and biological methods may not lead to the desired outcome.
Having said that, we’ll go through some methods to show how that can be made possible. For reference, most commercial growers here do rely on pesticide applications, and they need to be conducted on a regular basis with the right pesticides.
To grow peaches organically, you also have to be a little bit lucky. During peak time of production, the weather needs to be favorable for the grower. For example, during bloom a lot of rain is not good because then you get diseased flowers. During fruit ripening, a lot of rain is not good because the available organic products are just not strong enough to keep the diseases out.
But if you have a fairly dry period during bloom and fruit maturation, organically grown peaches can be produced here.
Dr. Melgar: We only have two organic peach growers/farmers in South Carolina. As far as I know, there are no organic peach growers in Georgia. It is really difficult here. Most of our organic peaches sold in grocery stores here come from the west coast. They’re grown in very dry climates with much fewer pests and diseases, so it’s perfect for organic growing.
We are working on strategies to try to reduce reliance on pesticides in peach operations here in the southeast. While commercial organic growers do apply organic spray every week, the most effective and popular strategy for backyard growers is “bagging,” using *specialized paper bags to cover each peach on the tree soon after fruit set.
Using this method, you just do one spray before bagging them to make sure they’re clear of any pest insects/eggs or pathogens before you cover them.
Question: From a cost-benefit analysis, does bagging make sense given the time and cost involved?
Dr. Melgar: The issue is not so much the labor cost itself. It takes one person one hour to bag all the peaches on a mature tree — about 250 fruits. That’s about $12 per tree on a farm, based on current labor costs. The challenge now is finding the labor to do that work, which is not a problem for home growers since they are the labor.
Question: What’s the lifespan of a highly productive peach tree?
Dr. Melgar: The average is about 12 years in a commercial operation. A peach tree can live 20 years or more, but their productivity declines after around year 12-13, which is why farmers take them out and replace them then.
QUESTION 2. It seems like there are an infinite number of pest insects and pathogens that can damage and kill peach trees here in the southeast, unlike in other regions of the country. What would you say are the top 5-10 pests or diseases that give backyard growers and farmers the most problems? And maybe also briefly describe when and how they cause problems for the tree or fruit?
Dr. Schnabel: There are only maybe a half dozen peach pests and diseases that you really need to be concerned about.
The biggest problems on the peach disease side for producing high quality peaches in the southeast are:
1. Brown rot caused by the fungus Monilinia fructicola. That’s the one that always needs to be battled, and it’s something that drives the spray program in commercial production.
Brown rot basically rots the fruit on the tree. And if you somehow manage to control the pathogen before harvest, it can still become a problem after harvest. The fungus can linger on the surface of the fruit. The fruit looks fine when you pick it, then three days later, it’s all rotten. We call that “latent infection.” The infection is there, but you don’t see it.
2. The second biggest disease problem is peach scab caused by the fungus Cladosporium carpophilum. That is something that occurs mostly after bloom, and it causes a cosmetic problem, a whole bunch of small dots on the fruit skin that can merge into bigger areas of ugliness. The peaches don’t rot, but they don’t look good either.
3. The third most problematic disease is bacterial spot, caused by the bacterium Xanthomonas campestris pv. pruni. It’s also something that we control after bloom up to pit hardening. It causes crater lesions that again don’t rot the fruit but cause substantial skin damage.
With regards to peach pest insects, the biggies are:
1. Peach tree borers (Synanthedon exitiosa) because it is the insect that can decimate your entire tree especially when the tree is young. For home peach production, you can apply beneficial predatory *nematodes that eat the peach tree borers. It’s a commercial product you can buy called NemAttack. You do a soil drench with them in the spring all around the trunk of the tree and they eat the borer larvae. [*The nematode species used to control peach tree borers are Steinernema carpocapsae and Heterorhabditis bacteriophora.]
It’s important you do this for at least the first four years; after that your tree is mature enough to be able to withstand some borer damage.
2. Peach scale is another pest insect that can kill your tree if left unmanaged. The most common species are white peach scale (Pseudaulacaspis pentagona) and the San Jose scale (Quadraspidiotus perniciosus).
The scales feed off the branch and scaffold limb tissue. If there’s enough scale, then there’s enough damage to suck the life out of the tree. Commercial growers use spray oil at late dormancy to suffocate the insects.
Dr. Melgar: You can put double-sided tape around the trunk or branches as a simple way to test to see if you have scales.
3. Another big pest insect problem that we should mention is plum curculio beetle (Conotrachelus nenuphar). You’ll see that little worm (larvae) inside the peach, which people find so disgusting.
Dr. Schnabel: The good thing about plum curculio is it doesn’t affect the health of your tree, only the quality of your fruit. It lays an egg into the peach, then you have worms in your peach. Control requires season-long applications of something — for organic growers that’s likely going to be combinations of Surround and Bt.
But it’s not enough to just apply them once and think you’re done for the whole year. The fruit is susceptible over many weeks, and you’ve got to stay on top of the spraying, every week or every 10 days, whether you’re growing organic or conventional peaches.
One advantage that homeowners have over commercial growers is they’re not growing a peach monoculture, so they’re not likely to have as much peach pest and disease pressure as a farmer growing many acres of peach trees. Monocultures are very challenging.
I think “success” of growing peaches organically depends on your expectations. If you don’t expect to have any pest insect damage or disease, you’re in trouble. If you’re willing to accept a certain percentage of culled fruit, you’ll be ok…if the weather cooperates.
Aaron [author]: That’s an interesting point to me from the perspective of a home grower, because only about 1 out of 5 of our fruits are picture-perfect and don’t have any damage. But I can still use that “ugly” fruit for pies, ciders, or other applications. Just cut off the bad spots, and it still tastes great.
3. We love growing and foraging mushrooms. A common mushroom we see fruiting in the fall is Armillaria mellea, aka honey mushrooms, which are actually a decent edible fungi. Honey mushrooms also happen to be a common parasite of peach trees. Are there preventative measures you can take to keep your peach tree roots from being infected by honey mushrooms? For instance, when planting peach trees, could you inoculate the roots with certain symbiotic endo or ectomycorrhizal fungi that could fend off honey mushrooms?
Dr. Schnabel: Armillaria mellea, honey mushrooms, actually don’t cause any trouble for peach trees. Desarmillaria tabescens is the problematic species in that it is the #1 killer of peach trees here in the southeast. [This disease is called Armillaria root rot (ARR).]
Desarmillaria tabescens (formerly called Armillaria tabescens) looks almost identical to honey mushrooms, but it was recently reclassified from Armillaria. It doesn’t have a ring around the stalk, which is how you can distinguish it from honey mushrooms.
This fungus actually has to be in tree roots from a previous tree in order to infect your peach tree. So the best thing a home peach grower can do is to not plant your trees where previously there has been other trees/forest areas that may have had the fungal disease. So, plant your new peach tree in a spot that previously had grass growing.
Other prevention options for Desarmillaria fungus root rot when planting your new peach trees are to remove all previous tree roots in the soil prior to planting or to plant in spots where previous trees were not infected.
These measures are much easier for home owners than monoculture peach farmers who replace their peach trees every 12 years into soil where previous trees’ roots were infected.
Commercial peach growers can use a cultural method of control for ARR that we developed here at Clemson called root-collar excavation (RCE). Unless you are growing your backyard tree in a spot where roots affected with the disease are buried, I’d not recommend it for home growers.
Commercial growers form a bed that is about 14″ high x about 3′ wide and plant the peach tree shallowly in that bed. That forces the tree to spread its primary roots in that bed, then go deeper into the soil. Then after two years of root establishment, you blow away/excavate that soil to expose the first few inches of those primary roots on top of the soil.
The method works because the fungus does not like to grow in roots beyond the soil line. If a tree root gets infected, the fungus will have to go through that area where you elevated your soil then bridge that gap into the tree trunk. But the fungus has difficulty doing that due to extreme summertime temperature fluctuations caused by the root exposure. If one root gets infected, the other roots will continue to uptake water and nutrients, keeping the tree alive and productive. For a while at least, until they also succumb to the disease.
We also have rootstocks that are less susceptible to ARR: those are peach-plum hybrid rootstocks that were only recently developed. One famous one is MP-29, but it’s not readily available to everyone because the nurseries are not able to produce as many as the market demands, making them very difficult for homeowners to get hold of. I think this method will end up being the ultimate solution to ARR.
As a general rule, fruit trees should always be planted shallow for the general health of your tree. Planting too deep (thereby suffocating the roots) is one of the most common mistakes inexperienced homeowners make.
4. To mulch or not to mulch? We’re big into no-till gardening, and always use wood chips or other mulches in our beds. Mulch provides a range of soil health and plant health benefits, everything from reducing the need for irrigation to boosting biological soil fertility/nutrient cycling to leveling out soil temperature fluctuations. Obviously, putting mulches around every peach tree in a large commercial orchard might not be practical, but do you think using mulch is a good idea for backyard orchards or small commercial operations? Any downsides?
Dr. Melgar: Yes to mulch! We are even trying to bring this into commercial orchards.
To clarify, you don’t want to do the “volcano mulching” that you sometimes see. It is better to have a tree with some of the roots at the base of the trunk being exposed (as Dr. Schnabel explained with the root collar excavation system) than having a mound of mulch around the trunk. As a rule of thumb, keep mulch a couple of inches away from the bark.
Peaches are very susceptible to “wet feet” [too much water] and can die if flooded for 48 hours or longer. Mulching improves soil aeration and soil structure and, as mulch decomposes, it also enhances soil water holding capacity and soil organic matter. The only possible downside I see is mulching may encourage voles, which can damage the base of the trunk when other food sources are scarce, and eventually also peach tree roots.
The second possible downside is that exposed soil (not mulched) might radiate more heat up into the tree during spring when late freezes threaten your blossoms compared to a mulched soil but, even in that case, we believe the difference should be minimal; to counteract this, you can water the soil really well during a clear, sunny day (before a night with freezing temperatures) and this water will help storing solar radiation as heat in the ground that can be released during the night and help maybe a degree or two.
But for overall soil and peach tree health, mulches definitely bring many more benefits than downsides for home peach growers.
Dr. Schnabel: Mulch also keeps the weeds suppressed underneath your canopy and enriches your soil with organic material and nutrients, which is very important for tree health.
5. I’ve talked to friends who’ve successfully grown various stone fruit crops (including peaches) on a small scale in the southeast and they seem to be having success using compost teas made from worm castings and/or Berkeley hot compost method. I think this method was popularized by Dr. Elaine Ingham, formerly of Oregon State University, with the idea being that various beneficial microbes present in these substances can outcompete or block pathogenic microbes, thus preventing infection or disease. There are also commercial products like Serenade available that use the same basic idea: using biology to fight biology. How effective — if at all — are these organic control methods/products for peach trees in the southeast?
Dr. Schnabel: I have no information about tea or tea extract to manage pests and diseases in the southeast. I could see that working in places like California where pest and disease pressure is low. But the disease pressure that we’re experiencing here… I’ve tested biologicals for scab and brown rot, and they all fail — especially for brown rot. They fail miserably, even the best ones.
I’ve had many companies telling me I’ve got the next best thing. I’m happy to test it, but nothing in the biological category has provided any relief in our tests. It’s [brown rot] is just such an explosive and difficult pathogen to control.
Where disease pressure is not as high, though, those biologicals can work.
The two organic peach farms here in South Carolina are trying everything under the sun, and it’s very hard. They’re trying Serenade, Surround, OxiDate, whatever they can find. If the weather conditions are not good, they won’t harvest any peaches that year. The biologicals just don’t have the necessary efficacy and do not penetrate into the leaf or fruit tissue like many synthetic pesticides do, and so they have less residual benefits to protect the fruit before and after harvest in our general climate conditions.
Question: During bloom, peaches are susceptible to disease introduction, especially if the weather is wet. Is there anything that an organic grower in the southeast can or should apply during bloom to try to reduce disease pressure?
Dr. Schnabel: The best (but not very effective) product would be sulfur. You may use it for blossom blight and fruit rot control.
6. We had pretty good success controlling pest insects on our peaches this year using Surround (kaolin clay). Are there any specific pest or disease control substances or products (whether homemade or commercial) that you’d recommend for backyard growers trying to stick to an organic approach? (For instance, my mom swears by neem oil, which she applied to her peaches up until the week she picked them – she’s in Summerton, SC.)
Dr. Melgar: In the next 2-4 years, we’re going to be testing certain essential oils in coordination with the University of Florida. Thymol [the major component of thyme oil] is one that shows promise, but we don’t know how efficacious it will be in an orchard setting. It seems to show good results in small tests. Another one is savory oil.
Dr. Schnabel: Those essential oils may be effective for diseases but are primarily for insect control, so we don’t know what — if any — effects they’ll have on peach diseases like brown rot. That’s one of the things we’ll be testing.
But I think for home peach growers specifically trying to grow organic, bagging is probably the best option available at this time. Once the fruit has set and the peaches are about the size of a thumb, you apply one more application of whatever pesticide you’re using to sterilize the surface of that tiny fruit. And that keeps the insect and moisture out.
When bagging, you need to make sure you do this during a dry period so the substance isn’t washed off and so that you’re not locking moisture in the bag with your peaches. The peaches and the foliage must be absolutely dry.
Then you don’t have to spray anything more on the fruit for the rest of the season. At that point, squirrels will probably be the biggest pest for home growers to deal with!
Question: If you’re growing organically, what spray application would you recommend a home grower use prior to bagging?
Dr. Melgar: In our field tests over two years, we found that Bonide was the only product that worked really well on wet years, but it’s not organic. On dry years, organic products like neem oil were also effective.
Dr. Schnabel: Circling back, I think the most important thing that a home grower needs to do for the long-term health of their peach trees is make sure that the planting depth of their trees is right. I see a lot of people — even commercial growers — plant their peach trees below the soil line.
The graft union should ALWAYS stick out of the soil and your root initiation should only be a couple inches below the soil line. For home growers, one easy way to make sure they plant their trees at the correct depth is to make sure the soil line of the potted plant is planted to the same depth as the soil line of the surrounding yard or garden. Then apply mulch and water the tree when needed especially during the first year of establishment.
7. Integrated pest management (IPM) is something I see being recommended a lot, even for large-scale farm operations. Can you speak a little about how IPM can be put to use by backyard peach growers? For example, are there specific plants that you recommend people grow near their peach trees to attract predators and/or deter pests? I remember reading somewhere that people used to plant tansy (Tanacetum vulgare) around their peach trees in the 1800s, the smell of which supposedly deterred peach pests while the flowers attracted predatory insects. But this could just be akin to a folk remedy that didn’t actually work.
Dr. Schnabel: IPM for disease management requires management of the orchard floor. For instance, we want to make sure that there is not an abundance of weeds that could harbor pests and diseases or stress trees due to competition for nutrients and water. We want to make sure that the tree is as happy as possible so its self-defense mechanisms are activated.
Any rotten fruit still hanging on the tree should be thrown on the ground or even better composted, not left on the tree. This reduces disease levels (inoculum pressure) the next year.
Pruning practices and yearly pruning/thinning is extremely important to reduce moisture in the canopy. The longer moisture lingers in the canopy, the more likelihood of disease development.
Leaving 600+ fruit on the tree makes it easier for fruit diseases like brown rot to take hold and jump from fruit to fruit. [250-300 fruit is ideal on a mature peach tree. That is one fruit every 4 to 6 inches of branch length.]
Other IPM strategies focused on reducing peach tree stress are not over- or under-watering, not over- or under-fertilizing, not having wild plums growing nearby since they harbor many peach pests and diseases. Anything that will reduce tree stress and reduce pest and disease pressure.
As far as specific plants that might be intercropped with peaches, we don’t really know since we’re working specifically with commercial peach monoculture operations. For homeowners, plant biodiversity is a good thing and an advantage they have over commercial growers, as long as they’re not growing plants that harbor pathogens.
8. Genetics obviously plays a huge role in plant hardiness. What are the hardiest peach varieties you’d recommend for backyard growers?
Dr. Melgar: For bacterial spot, ‘Redhaven’ — which is a popular one — is very resistant.
Dr. Schnabel: There are no cultivars that are completely resistant to brown rot, but ‘Contender’ has some resistance.
We should also recommend to home growers in the southeast: do NOT grow nectarines. Don’t even bother. They’re extremely prone to pests and diseases, no matter what you do.
9. Surgeons sanitize their hands and tools before operating on the next patient. Do you recommend orchardists do the same thing when pruning their trees to prevent spreading disease from tree to tree?
Dr. Melgar: As long as you’re pruning your trees when it’s dry outside, you should be ok. Pruning should be done in January and February and you really want to make sure you have very sharp tools so you’re making clean cuts. Jagged cuts, leaving long stumps, or pruning too close to the branch provides greater portal entry for diseases. Optimally, we recommend leaving about a ¼ inch mini-stub.
Dr. Schnabel: And homeowners need to understand that pruning is not bad for a tree, it’s essential for the tree’s health. It prevents the branches from snapping in summer when fruit load is pushing limbs down. It keeps moisture out of the canopy, which reduces pest and disease pressure.
If a homeowner isn’t willing or able to do these things we’ve outlined, they should not grow peaches here. They should grow something easier.
9. Any other recommendations for backyard peach growers? Or other websites/books/resources you’d recommend?
Dr. Melgar: Homeowners often prune too early, which can induce early blooming, then the flowers freeze off. We have plenty of commercial growers that prune even when their trees are in full bloom. This is perfectly fine — especially if you have early varieties. You only need about 10% of your flowers to produce in order to have a full crop.
Another thing is not to assume that a big box garden center has peach tree varieties appropriate for your growing zone. For instance, in our area, you want varieties suited for about 600-800 chill hours. So if you get a Florida variety bred for low chill hours, you won’t get any fruit here.
We have a lot of other helpful resources available for backyard peach growers here: https://www.clemson.edu/extension/peach/backyard.html.
10. You probably eat a lot of peaches; if you had to choose one, what’s your favorite peach recipe?
Dr. Melgar: I slice and freeze them, then use them throughout the winter. I love them on dairy products like yogurt and ice cream.
Dr. Schnabel: I like to eat them fresh. I actually like them a little crunchy when they taste sort of like an apple. I also like to let some of them get so soft that the skin just peels right off. Then they’re super sweet and dripping with juice.
III. Key takeaways: a printable quick guide to growing organic peaches in the southeast US
Click here to download or print a PDF version of the organic peach growing guide seen below:
We hope this article helps you grow your own homegrown organic peaches in the southeastern United States! And when you bite into your first big juicy peach of the season, be sure to thank Clemson University’s Drs. Schnabel and Melgar.
Other fruity articles you’ll love:
- 30+ easiest fruit species to grow organically in the southeast US
- How to grow fruit year round in your garden
- How to use American beautyberries as food and insect repellent
- Aronia: how to grow or forage the world’s highest antioxidant fruit
- How to grow, forage, and eat Japanese and American persimmons
- How to grow or forage native passionfruit
- How to grow and use ground cherries
- Complete guide to growing elderberries
- How to grow pawpaws: North America’s largest native fruit
- How to grow citrus in pots in any climate zone