Added on July 5, 2021 Sara Swanson

July 2021 Gardening Advice

Decrease Font Size Increase Font Size Text Size Print This Page Send by Email

Colorado potato beetle

submitted by Jennifer Fairfield, Garden Mill and Manchester Community & School Gardens

My grandmother always said that if you don’t have something nice to say (about a person), you shouldn’t say anything at all. So, I am not going to say anything at all about the weather in June! Instead, I will say how much I am enjoying my gardens. Everything is growing like crazy in my vegetable garden, and lots of things are starting to really bloom in my flower beds (the picture above is the butterfly weed in one of my gardens). The not-to-be-mentioned weather has apparently agreed with my gardens. I hope yours are doing as well!

Oh – one mention of the weather I can’t let go. The frogs and toads are really enjoying it. I am finding frogs absolutely everywhere around my house, and I do mean everywhere! I came in from taking out the trash last night, and apparently had a hitchhiker! A gray tree frog jumped off of my pant leg and onto my sofa, giving me a momentary startle. Fortunately, I was able to grab it and usher it outside before my cats saw it. That would not have been pretty!

I took a week away from the store last week, and I had a great time working in my yard and gardens. I got such a sense of accomplishment from all that I got done. Of course, there’s always more to do, but at least for a brief moment, I can feel like I am (almost) caught up! Here are some tips to help you stay caught up in your yard and gardens:

In the vegetable garden:

July is the time when many insect pests are really wreaking havoc on vegetable gardens, so let’s talk about how to deal with them. First — it’s important to know that there isn’t a one-size-fits all solution. You need to know what’s eating your plants so you can be sure to use the proper controls. Here are some of the ones that might be causing you problems (and if there’s something eating your plants that I’m not covering here, please feel free to email, call, or stop in, and I will try to help you find a solution to what’s bugging your plants):
- Aphids generally hang out in large groups at the tips of stems (they like succulent, new growth best) and on the undersides of leaves. Aphids come in lots of colors, including green, black, yellow, orange, red, and white. A good squirt or two of insecticidal soap is all it takes to neutralize these pests, but you need to spray them directly for it to be effective. Spray them as soon as you see them. Aphids reproduce at an amazing rate, and can do a lot of damage if left to their own devices.
- Cabbage moth caterpillars can easily be picked off of your plants and squashed. The hard part is finding them. Look for them on the undersides of the leaves (though they may also be on the tops), and look really closely — they are experts at camouflage. Even if you find one or two, there may be more that you miss, so check back again in a day or two. One clue to where to find them is to look for their excrement. If you see fresh green-black pellets on the leaves, the caterpillars are likely nearby. If you’ve got too many to pick off and squish (or the thought of doing so makes you cringe), Bt insecticide is an effective killer. Just be aware that Bt kills all caterpillars — including butterfly and moth caterpillars — so use it very carefully.
- Colorado Potato Beetle eat the leaves of tomatoes, peppers, and eggplant, as well as potatoes (and tobacco, but I’m guessing not too many of us are growing tobacco). They are difficult to control because they have developed resistance to almost all pesticides. It’s actually the older larvae (what are known as the 4th instar) that do the majority of the damage, and potato plants are at their most vulnerable as they are forming potato tubers (around the time of flowering). In general, the best way to control these pests is to start as soon as you see any sign of them — before you get overwhelmed by numbers of them. Picking adult beetles and larvae off of your plants and dropping them into a bucket of soapy water is the most effective treatment. If you have to resort to pesticides, neem oil and spinosad are the most effective treatments available — chemical treatments just don’t work — but they are really only effective when the larvae are in early stages of growth. Try one, and if that stops working, try the other.
- Cucumber Beetles come in two different versions — yellow with black stripes and yellow with black spots — but the striped ones tend to be more prevalent in our area. These pests are a real problem for most plants in the cucurbit family (summer squash, winter squash, melons, pumpkins, and cucumbers — cucumbers being their favorites) in three different ways. First, the adult beetles eat the leaves and flowers of the plants, causing stunting of the plants and keeping your plants from producing fruit. Second, the adults can carry bacterial wilt disease as they travel from garden to garden. Third, the larvae of the beetles feed on the roots of plants. Very young plants are the most susceptible to cucumber beetles, so really keep an eye out early in the life of your plants. Insecticides have not proven to be very effective against them, but row covers and insect netting can be, as long as they are secured to keep the adults from getting under them — just be sure to remove the covers when your plants start to flower, so that they can be pollinated.
- Flea beetles and Mexican bean beetles are a difficult to deal with, because they are escape artists. Flea beetles are tiny, black beetles that eat tiny holes in the leaves of your plants — it looks like somebody shot your plants with a BB gun. They eat a number of different plants, and are hard to spot. Mexican bean beetles pretty much just stick to eating bean plants. They are the size of ladybugs, and actually look a lot like ladybugs, but are generally yellow to orange in color, and always have exactly 16 black spots on their wings — 8 on each wing. Ladybugs, on the other hand, come in a variety of colors, but generally have fewer spots. Both flea beetles and Mexican bean beetles jump really far, really fast, when they are threatened, so trying to spray them is not very effective. However, diatomaceous earth can be effective against these critters. Controlling both of these creatures is important — flea beetles can spread diseases to your plants, and Mexican bean beetles can decimate bean crops in short order.
- Japanese Beetles are definitely one of the most hated garden pests. While they are a problem in both Vegetable gardens and flower gardens, I’ll address those below, in the flower garden section.
- Slugs are one of my least favorite creatures in the garden. Aside from the fact that they’re slimy and gross, they can do a lot of damage in the garden. Slugs mostly feed at night, because they dry out too easily in the sun. So, if you are seeing lots of damage to your plants that seems to show up overnight, and you can’t find any insects, you probably have slugs. If you look under your mulch, you might actually see them hiding there (they also really like lettuce, and you can often find them within the leaves). These guys, because they stay hidden most of the time, can be hard to control. Diatomaceous earth, which can be sprinkled around the plants, is one option. It is scratchy, and will shred the soft bodies of the slugs as they try to get to your plants. You can also use window screening, cut into circles, and placed at the base of your plants. Slugs generally avoid anything scratchy, so will stay away from screening.
- Squash bugs and Squash vine borers are both very destructive of summer squash, winter squash, and pumpkins (and sometimes cucumbers and melons). Of the two, squash vine borers do the most damage, and are the hardest to control. Two things can be effective in preventing the squash vine borer moth from laying eggs on your plants. The first is row covers. Cover squash plants with row covers or insect netting now, and secure them so that the adult moths can’t get under them (that's one of them in my garden in this picture). Leave covers in place for about two weeks (though remove them sooner, if your plants are flowering, so that the flowers can be pollinated). The second option is to wrap tin foil over the base of the stems of your plants. This helps to deter the adult moth from laying eggs. Neither method is foolproof, so keep any eye out for the eggs. Look for tiny, reddish-brown dots on the stems. Scrape them off carefully, so that you don’t damage the plant, and drop them into a bucket of water. Squash bugs generally lay their eggs in clusters on the undersides of leaves. You can scrape them off, or simply remove the leaf itself, and drop in water. If you miss the eggs, you may see the nymphs — gray/green little bugs that scurry across the leaves in large groups. Those can best be treated with neem oil.
- There are lots of different pests out there, and it’s impossible for me to try to cover them all here. If you’re not sure what’s eating your plants, send me pictures, or come in. I can often (though not always) identify the culprit from the plant that is being eaten and/or the damage that is being done. From there, we can come up with a potential solution.
Weeds are also a big problem in gardens at this time of year, and keeping up with them can be a real chore! The best thing to do is to try to get them while they’re small, mostly because they are easier to pull out before their roots are too established. Since weeds compete for water and nutrition with the plants you want, don’t let them get out of control. At this time of year, crabgrass, knotweed, plantain, spurge, and thistle are the most prominent of the weeds. Of them thistle can be the hardest to deal with, but all pose their own special challenges. Not sure what you’re seeing in your garden? There are some good apps for smartphones that can help in identification — just snap a picture and upload it for identification. Among them, I have found Google Lens, Picture This, PlantSnap, and PlantNet to be very helpful, though some of them only allow you to ID up to a certain number for free. The University of Missouri has an app, ID Weeds, that lets you search for weeds by name or by the plant’s characteristics, and gives you some information about the weed. None of these apps tells you how to get rid of them, unfortunately. Some options that don’t include pulling include using a pre-emergent in the early spring and spraying for existing weeds. Corn gluten, an organic pre-emergent, won’t do anything for weeds you already have. What it will do is help to cut down on weeds over time, by keeping weed seeds from germinating. An organic weed spray that I have found to be very effective in my own yard is Bonide’s Burn Out Formula II. It is a non-specific weed killer, which means it kills pretty much everything in comes in contact with — even things you don’t want it to — so use it very carefully, and don’t spray when there is any kind of wind that might carry it to plants you aren’t trying to get rid of.
Early in the month is a good time to side dress your summer crops — especially because of all the rain we’ve been getting lately, which can wash away fertilizers you put down earlier and can make it hard for your plants to take up the nutrients they need. Side dressing is just the simple act of giving your plants a mid-season boost of fertilizer. It provides the plants with a little extra food when they need it most — as they are doing the most growing and as they are producing flowers and fruit. By the time they are ready to start putting out flowers, the plants have used up most of the available nutrition in your garden. Providing a little more fertilizer at this point will make a big difference in whether your garden produces in abundance or just so-so. The term side-dressing really just means to apply fertilizer around the plant, in the root zone. Don’t just sprinkle it on top, though — carefully work it into the top inch or so of soil. Fertilizer left on top of the soil often will just wash away before it can break down and be useful to the plant. Don’t get any closer than about four inches from the stem of the plant, as you want the food to be available to the new root growth as the plant is growing and putting out more roots.
One very common issue with tomatoes, peppers, eggplants, and squash that occurs when we are getting the kind of rain that we have been seeing is blossom end rot. People are often led to believe that the problem is solved by adding calcium to their soil, but a lack of calcium is not always the problem. The problem is often that too much water (or even too little water, though that is not as common) makes it difficult for the plant to take up what calcium is in the soil. When we are getting a lot of rain, there’s not a whole lot you can do to fix the problem, unless you can somehow provide better drainage for your plants. If you have had your soil tested and it shows a lack of calcium, bonemeal, lime, and even crushed eggshells are good ways to add some back into the soil. There are other issues that can cause blossom end rot.
Keep up with your program of fungicide spraying (or start one, if you haven’t yet). There are a lot of diseases that really get going as summer progresses, especially on tomatoes, cucumbers, and squash. Treating your plants with an organic fungicide on a regular basis can help keep them from succumbing to disease, which means that you might actually get to eat a lot of what you planted! If you’re not sure how to tell what’s ailing your plants, Cornell University’s Vegetable MD Online at http://vegetablemdonline.ppath.cornell.edu/cropindex.htm is a great resource. But don’t wait until you see disease to treat it — most of the diseases can’t really be treated, but need to be prevented. So treat your plants regularly — generally weekly, but more often when we’re getting a lot of rain.
July should be harvest time for many crops. Spring crops, such as lettuce, spinach, and peas will mostly finish producing this month, if they didn’t already bolt and go to see in the high heat we had early in June. Summer crops, such as zucchini, cucumbers, and early tomatoes will generally just be getting started by the end of the month, though we may see some coming in earlier than usual, due to the heat and rain.
Garlic is generally ready for harvest between the middle of July and early August, depending on the variety and when it was planted (fall vs. spring). If possible, stop watering your garlic about three weeks before you expect to be harvesting (I say “if possible” because none of us can control Mother Nature!). You can tell that garlic is ready to be harvested by the foliage. When about one-third of the leaves have yellowed and withered, it’s time to check on your bulbs. Gently wipe some of the soil away from a bulb, and check the size and form of your garlic. If it looks like a good size, it’s ready to come out. If not, leave it for another few days to a week, and check again. Don’t leave garlic in the ground too long past peak harvest time though, as this could lead to rotting, and you may want to pull it earlier than usual if your garden is having flooding issues, for the same reason. Better some smaller heads of garlic than rotted garlic! When it’s time to harvest, don’t pull the bulbs out by the foliage, as you will likely just tear the foliage off and damage the bulbs. Instead, carefully loosen the soil around the bulb with a garden fork, and then get up under the bulb with a trowel or shovel.
July is also a time for planting and starting new seedlings for fall harvest. If you want to have broccoli and cabbage for fall, start your own inside no later than July 10th, transplanting the seedlings into your garden when they are about six weeks old (don’t forget to slowly introduce them to the sun over the course of about a week before putting them into the garden, to avoid sun scorch). They should be ready for harvest by early October. These can be good “succession crops” to be put into the garden in place of things like onions and garlic, once those have been harvested.
You can plant late season successions of lettuce, spinach, peas, beets, carrots, and Swiss chard at the end of the month, to be ready for picking before it gets too cold. But wait to plant late-season radishes until early or mid-August, as it will generally still be too hot at this point for these cool-weather lovers (they mature very quickly and will bolt in the heat of August before they can get big enough for eating).
I know that it sounds crazy right now, but don’t forget to water your veggie garden regularly as summer goes on. This rainy weather won’t go on forever (even though it might seem like it), and your plants generally need about an inch of water every week. A good soaking once a week is better than a little bit every day or two, but when the temps are really high, and especially when accompanied by wind, a little more water is even better. Don’t overdo it, but definitely make sure that your soil doesn’t totally dry out between watering. That’s a great way to stress your plants.

In the flower garden:

Much like in the veggie garden, keeping insects under control gets to be more of a challenge as we move into July. In my flower gardens, I’m seeing aphids on my asters, sawfly larva (pictured) on my hardy hibiscus, and Japanese beetles on everything! Insecticidal soap has been working well on the aphids and sawfly larva, but the best way to deal with Japanese beetles is to simply pluck them off the plants and drop them into a bucket of soapy water. The soap coats their wings, making it impossible for them to get out of the water, and they eventually drown. The best time of day to do this is in the afternoon, when it has warmed up, as that is when they are at their most active, though do it whenever you can (I make it a morning ritual, before I leave for the store). Getting as many as you see on a daily basis will help keep them under control. If you wait too long, the few you have will suddenly turn into a mob, as they will signal their friends when they have found something they like in your gardens.
If you are using insecticides of any kind, be aware of when to apply them. Different insects are active at different times of day, and some pesticides work best if sprayed directly on the pest. Also, be aware of bee and butterfly activity in your flowers, and don’t spray any insecticides when you see them around, or at least do targeted spraying, instead of broadcast spraying. Always read labels completely and follow instructions carefully. Regardless of whether you use organic or non-organic products, they are poisons, and can be harmful to bees and butterflies, as well as you, if not used properly.
Additional pests I have been getting a lot of questions about controlling lately are rabbits and deer. They can do an enormous amount of damage in very little time, and are hard to control, because they are often out when you’re not. I cannot recommend Epic’s Deer Scram and Rabbit Scram enough for the control of these creatures. I have used both in my gardens for a number of years now, with great results!
Be sure to fertilize roses throughout the month, but stop fertilizing at the end of the month to allow the new growth to harden off before winter. Also remove diseased leaves immediately, and pick up any that have fallen. Aphids and mites can be major rose pests that can cause serious damage if not kept under control. Careful spraying when these pests are spotted is generally all that is necessary. These tasks, along with regular fungicide spraying will help keep your roses healthy.
As in your vegetable garden, keep weeds under control in the flower garden, so they don’t compete with your flowers for moisture and nutrients.
Cut back perennials that have finished blooming.
To keep container annuals blooming all season long, be sure to fertilize them regularly. With frequent watering, fertilizer tends to get flushed out of the container, so regular feedings are a must. Also, don’t forget to deadhead. By removing dead flowers, you encourage the growth of new ones throughout the season.
Keep an eye on watering needs for all your plants. It's easy to get complacent with all the rain we've had. Before you know it, the rain will have stopped and the sun will be beating down and drying everything out again. Even if it continues to rain, pay attention to containers that might be under porch eaves or otherwise might not be getting the benefit of all the rain.
Once Mother Nature does turn off the faucet, keep an eye on any trees and shrubs you have planted this year (and really any that were planted in the last two to three years). It takes a while for their roots to become efficient at taking up water from the soil, so making sure that they are well watered is essential to ensuring their success. Tree watering bags and donuts can be life-savers (literally for your trees, and figuratively for you) during extended dry periods like we had in the early part of June. You only have to fill them up once or twice per week, and they slowly water your trees for you.
Do not apply fertilizer to trees or shrubs after the Fourth of July, in order to avoid a flush of new growth late in the summer that doesn’t have time to harden before winter.
Finish up pruning of trees and shrubs this month or early next. Pruning too late in the season can also encourage new growth that will not have time to harden off before winter sets in.
When you’re out working in your gardens and yard, keep an eye out for ground-nesting wasps and yellow jackets. They don’t take well to having their homes stepped on, sat on (as I almost did the other day), or run over with lawn equipment, and will let you know in a hurry. I am generally a big proponent of the live-and-let-live approach to these creatures, but if they are in areas where they pose potential harm, especially to someone who is allergic, eliminating them may be necessary — and can be done relatively easily, without chemicals. Go out at night (when they have all returned to the nest) and cover the entrance hole to the nest with a clear glass bowl. Dig the rim of the bowl down into the soil around the hole, so that there is no gap between it and the soil where the wasps can escape. The wasps will not try to dig a new exit hole (which they will do if you simply fill the hole in with soil), because they will be able to see the sky, and don’t understand that they can’t actually get out. They will eventually die in the nest, and you can remove the bowl — just keep an eye on it to make sure you haven’t seen any activity for a couple of days before you remove the bowl.

Lawn:

When mowing this summer, leave your grass between 3 and 4 inches tall, and only cut off the top third of the blades at each mowing. Keeping your grass a little higher will help it retain moisture during the hot, dry summer we usually have, and will help suppress weeds. This is not an easy task to keep up with when it’s as rainy as it’s been, especially because it’s much better for your grass not to mow when it’s wet. Mowing when the grass and ground are wet can be bad for your lawn in two ways. The first way you damage your lawn by mowing when it’s wet is that the weight of you and your equipment can compact the soil, making it difficult for the roots to get the air they need to survive. The second issue is that leaving clumps of wet cut grass on your lawn encourages fungal diseases. Wait to mow until the grass has had a chance to dry out, whenever possible.
The larva of those nasty Japanese beetles we’ve been talking about are the grubs that will be eating your grass roots later in the season, causing patches of brown, dead grass that, unlike grass that is dormant, won’t be growing back. If you are seeing a lot of adult beetles now and can’t keep them under control (a next-to impossible task), the best thing you can do is to control the larva that will be eating your grass roots later this month. Milky spore is a long-term control option that is actually a bacterial disease that kills the grubs when they ingest it. It can be effective for many years, but also takes a few years to kill off all of the grubs, so don’t expect immediate results.

For the Birds:

Keep your birdbaths full and consider putting out additional baths or even filling things like overturned trash can lids or large saucers with water for them. The dry conditions we generally have in summer are as difficult on birds as on our gardens, and they are going to be looking for water wherever they can find it. One place they may try to relieve their thirst is in your garden — by biting into and sucking out the juice of your crops! Making sure they have a consistent source of water may save your harvest. Just be sure to dump the water and refill it every day, to discourage mosquitoes from laying eggs. Another way to control mosquitoes in bird baths is to install a water wiggler or birdbath dripper. Constant movement of the water makes for inhospitable conditions for mosquitoes to lay their eggs.
Keep hummingbird feeders cleaned out and filled. Sugar water left out in the heat for a number of days can breed bacteria that is harmful to the beautiful birds visiting your feeders, so be sure to clean them out every few days.