Every week across all of the joegardener and Growing a Greener World social media channels and the Online Gardening Academy courses, I receive scores of questions and requests for advice, and I try to answer as many as possible. For this week’s podcast, I’ve rounded up some of your most frequently asked gardening questions for June to bring you answers that you may be looking for too at this time of year.
Even though podcast listeners and Online Gardening Academy enrollees come from all over the country, it’s common to find a recurring theme among gardening questions. What follows are several of the topics that have popped up lately and the specific information gardeners want to know.
Using Grow Bags
Grow bags have really caught on in the last few years, and this year they are especially popular among new gardeners who have limitations on space or who have yet to build raised beds. The bags are a great solution because they are inexpensive and at the end of the season they can be emptied, collapsed and stored — taking up very little space. Plus, a used grow bag is as good as new for years to come.
The No. 1 gardening question we’re getting right now is, what size grow bag do I get and where do I get it? As far as where to find grow bags, check with your local garden center or go to Amazon. Generally, these nylon fabric bags are the same from any supplier.
Grow bags come in a variety of sizes, but the minimum useful size that I would recommend is five gallons. To give you an idea of how big that is, visualize a five-gallon bucket, though a bit wider and not as tall.
I am of the firm belief that the more room that you can give your plants to grow the better off and more productive those plants are going to be. With adequate room to grow roots in proportion with top growth, plants will be more vigorous and more drought tolerant. So for that reason, I grow in seven-gallon grow bags. That two gallons can make a difference.
Seven-gallon grow bags are great for smaller, bush-type tomatoes as well as peppers, lettuces, radishes, onions and garlic. But for a large, indeterminate tomato plant, I am growing in 15-gallon bags.
When choosing a size, keep in mind that the larger the bag, the more soil or mix you’ll need to fill it up — and that can impact your budget.
Because grow bags are fabric, they drain really well — and that means they can dry out easily. So when using grow bags, it’s important to water frequently. You can make it easier on yourself by installing an automated drip irrigation system, which puts watering on autopilot.
Also among the frequent grow bag gardening questions is what kind of soil to use. A lot of people know that I’m a stickler for having the right kind of soil based on what you’re growing in, and with grow bags, the right kind of soil is well-draining. You want your plants to be getting enough water and for soil to never dry out, but in the confined space of a grow bag, the water can really build up in heavy soil.
If you keep watering or it keeps raining, the heavy soil is just going to get wetter and wetter and wetter, and basically become soggy — and you do not want that. I can’t think of any vegetable plant that is happy in that kind of growing environment. You need drainage in order for those roots to get the air that they need.
The magic formula for grow bags is soil that retains enough moisture and yet drains really well too. You can buy potting mix, container mix or potting soil — each of which usually has a lot of peat moss in it, plus some perlite for drainage and air space. Some commercial mixes contain finely ground wood fines, which is essentially finely ground forest products, and some contain compost. And unless you’re buying an organic container mix, the mix may also contain slow-release synthetic fertilizer.
You can make your own mix by putting those individual components together and mixing it all up. If you want to skip the peat moss, which a lot of people like to do, then get some high-quality topsoil and compost. Use about 30% topsoil and 30% compost, and for the remaining 40% make the mix airy and light with perlite and add finely ground or triple-shredded wood mulch. You can also mix in a slow-release fertilizer if you want. Also consider composted manure or vermicompost in the mix for more nutrients and microbiology activity.
To keep plants in grow bags fed, you can periodically apply a soluble or liquid fertilizer every week or two.
Another consideration is staking. For large plants like indeterminate tomatoes, a couple of large stakes stuck in the bags won’t be enough to hold them in place. Place those bags next to something that can support those plants, like a mounted livestock panel. You’re securing it to the panel, and the grow bag is just providing the foundation and the soil for the roots.
Grow bags work for everything but are especially good for plants that trail or vine or stay in a shrub-like form, like bush beans. One of my favorite applications for grow bags is growing potatoes because when they are ready for harvest you can just dump the bag out without worrying about damaging the tubers.
The Season for Tomatoes
It is the season for tomatoes, and a lot of people are excited about starting their own seeds this year and nurturing them along until it’s time to get them outside. Along the way, they’re noticing that the plants are blossoming, even though they may be haven’t planted them out yet. Gardeners see those flowers and maybe even tomatoes forming and they want to know, what do you do with those? Do you pull them off or do you leave them on? The answer depends on who you ask.
For the longest time, I’ve always said, go ahead and pull off those first flowers. They are usually coming on as those seedlings are still inside and you’re in the hardening-off process, and the rationale behind pulling them is that you don’t really want energy to be diverted away from the plant’s growth while it’s settling in outside. Instead of trying to produce fruit that early, you really want the immature plant to get acclimated, then really kick into gear.
I’ve had great success with that philosophy in the past, and I have no regrets and no complaints, but I’m changing my ways this year thanks to conversations I’ve had lately with my good friend and co-instructor in the Online Gardening Academy course Growing Epic Tomatoes, Craig LeHoullier.
Craig is a real authority on tomato growing, and he has never pulled off any tomato flowers at any stage. So as early as they come on, he lets them be, and he gets a ton of tomatoes each year on the couple of hundred plants that he puts in the ground. And he says he’s never done it any other way. You can’t argue with success.
What to do about tomato suckers is also among the popular gardening questions this time of year. A sucker is that little shoot that comes out between the main stem and the side branch at a 45-degree angle. So the question is, do you pull those off? And here again, you get people on both sides of the fence: Yes, you pull it off because it’s going to detract from the energy that the plant needs. And no, you don’t, because you’re cutting down on the overall production. The best choice is whatever works for you.
Each sucker that emerges on your plant is going to become a fruit-bearing branch of its own. That can be a good thing if you have room for those branches without sacrificing light and air circulation. Light and air circulation are super important because tomatoes are so susceptible to various diseases, and one of the ways that you can minimize that is to provide plenty of sunlight and air circulation.
Cutting off suckers on a caged tomato plant, which has little room to spread, is usually the way to go. But your plants may be also trellised with plenty of room to grow. Well, you can also choose a hybrid method — I don’t take them all nor do I leave them all. I assess every plant in real-time and remove the suckers that lack the trellising or cage space to support them.
If there is enough room for that sucker to be its own fruit-bearing branch without crowding out the others that are already there and cutting down on the light and the air circulation, I let it grow. But if it’s going to cause some crowding and cut down on light near circulation, I pop it out.
You can remove a sucker by bending it back and forth, and it’ll snap off right at the base. I also like to use micro snips, which are thin, pointed, little pruners.
When I remove a sucker, I don’t toss it out. Instead, I plant it in a 6-inch-deep container and ID it and date it with a plant tag, which I have at the ready in the garden. I place the container on a potting bench in the shade for one or two weeks so the sucker can root and settle in. After that, it’s ready to go out in the sun.
That sucker is a genetic clone of the plant it was removed from and it’s an insurance policy if the parent plant dies.
One of the gardening questions I saw a lot over the past week or so came with pictures of yellowing foliage on tomato leaves. Gardeners wanted to know what caused that yellowing, and they assumed it was a disease.
The standard assumption is that tomato diseases at this time of year are caused by early blight, which is usually the first disease to show up, starting on the bottom of the foliage and working its way up the plant. However, don’t assume that’s the absolute answer.
Little dots on those yellow leaves indicate a pest issue, specifically a bug with piercing/sucking mouthparts — a stylet that is basically like a straw used for sucking vital fluids from the leaf. The damage is almost always from the underside of foliage, which is where they hide out and do their damage while feeding.
You may also look under leaves and notice residue, such as frass from the bug droppings. Frass is often easier to spot than these bugs because they’re so small. For example, a lot of times you need a magnifying glass to see a spider mite, but spider mites do a lot of this damage. The culprits could also be thrips, whiteflies, aphids, or a tomato or potato psyllid.
Many pests fly away before you notice the damage, but spider mites tend to stick around. Insecticidal soap is a good organic control for spider mites. Make targeted sprays on the plant foliage, taking care to avoid overspray that can kill beneficial insects. You can also cut off those yellow leaves and throw them away, perhaps removing the pest at the same time.
Flea beetles are tiny, shiny, eighth-inch bugs seen on the top side of leaves. They leave little holes in leaves and really love to go after eggplants, which, like tomatoes, are in the nightshade family and experience many of the same pest issues. Insecticidal soap will work on flea beetles, but as the plant gets bigger and tougher, flea beetles aren’t as much of an issue. And also keep in mind, a plant can take a significant amount of foliage damage before it really becomes impacted, so don’t freak out.
Controlling Plant Diseases
As I mentioned, early blight is the plant disease that most of us are going to see right now on our tomatoes and peppers. Common gardening questions that arise are, what is this disease and what do I do?
Diseases are going to make their way into your garden no matter what you do, because they come in mostly through the wind. We can also bring diseases in on our hands and our clothes and our shoes, and all kinds of different ways — but we can’t control the wind and that’s why I say don’t blame yourself.
Best practice-wise, you can minimize or cut down on the chances of making the problem worse. One way is practicing good garden sanitation. The biggest thing that you can do is avoid handling plants when they’re wet because water is a really common way for diseases to spread from one plant to the next.
Another way to help control the diseases in your garden is to remove what’s there. You’re not going to reverse a disease and you can’t cure it, but you can minimize the spread by removing the infected parts that you see to cut down on spore transfer. However, there’s a right and a wrong way to remove disease plant material.
Work with a plant that’s dry, and use a clean cutting tool that’s sharp. Between every few cuts and between every plant, spray your blades with alcohol. You want to get those fungal spores off your blade so you won’t transfer a disease unwittingly to your next plant.
When removing diseased leaves, follow those leaves all the way back to the branch and just cut the whole branch off. That will save you some trouble because otherwise, you’re going to just be coming back the next day and doing it all over.
Throw away diseased plant material, and don’t put it in the compost. Put it in a bag and tie it up, and get it off your property. If you throw it in the compost pile, those spores can survive because most home composting operations don’t get hot enough to kill fungal spores.
One more step that we can take that can make a big difference is to spray with a fungicide. If you’re an organic gardener, you’re going to use copper fungicide, either in powder form mixed with water or a liquid concentrate. Follow the instructions on the packaging always regarding concentration and application frequently, and make sure that you get both the tops and underneath the leaves to have any chance of control. Fungicide works by coating the leaves, and the methodology is to prevent the ability of that spore to infect the leaf.
If you’re a non-organic gardener, the most common fungicide in the home market goes by the trade name Daconil, and the active ingredient is chlorothalonil. And that works pretty well too. But don’t overdo it with the copper or the synthetic version, cause they have their own risk as well: Copper is a heavy metal and it can build up in your soil, and chlorothalonil is a known carcinogen, at least for labeling purposes in California.
The Quick and Dirty On Watering
People want to know the best time to water and how much is enough. The simple answer is, most plants need about an inch of water per week, considering all sources of water. So if that’s rainfall great, that’s it. But usually, you’re supplementing the rainfall with your own watering. But who really measures an inch when you’re out there supplementing? Not many people that I know. Just keep an eye on the soil moisture. You just want even moisture. You don’t want it to be too wet; you don’t want it to be bone dry. Your plants will show you they’re unhappy, and you’re going to have to come up with your way to know that your plants are getting enough water.
The best time to water is either early in the morning, so the plants have time to take up the water before the stresses of the day come on, or late in the day, when there is less heat stress and less evaporation. Either way, get the water to the soil and roots without getting any of the foliage wet.
You want to get your plants off to the fastest, best start possible, and you want to help any way you can. So one of the natural things to do is to fertilize them. But then the question is, what do I use and how often do I do it?
First of all, focus on your soil and make that as healthy as possible. When you create healthy soil with lots of compost, you’ve got probably all the nutrients your plants need to make it through the growing season productively and healthy.
If you want to supplement, there’s nothing wrong with that, but fertilizer can be very powerful, and too much of a good thing can actually cause damage to your plants. So if you think a little bit is good and more is better, that’s not the case with fertilizer.
Most of the potting soil that you get these days has a slow-release synthetic fertilizer in it that will feed your plants for a number of months. Organic potting mixes have some organic equivalent. Either way, the nutrients are already there and you don’t need to supplement the soil with fertilizer.
In a raised bed or in-ground bed, in addition to building the soil health, you might want to add a slow-release fertilizer to begin with. Alternatively, after the plants had been in the ground for about a week, add a mild fertilizer like a 5-1-1 fish emulsion, which is highest on the nitrogen side so it promotes vegetative growth initially.
Once plants begin to produce flowers or fruit, I switch to a fertilizer that has a higher middle number, which is phosphorus, with a ratio of about 2-3-1. Phosphorus promotes flowering and fruiting, while high-nitrogen fertilizer can be detrimental at this stage because plants will focus on continued vegetative growth instead.
Whatever fertilizer you choose, whether it’s organic or synthetic, the nutrients work the same chemically as far as the plants are concerned. The difference is in how the nutrients are released. Organic fertilizer stays put, provides continual feeding and becomes available to plants slowly as microbes break it down. Synthetics are often water-soluble, delivering nutrients instantaneously but with a risk of fertilizer burn and also leaching into water bodies, contributing to algal blooms.
I hope this podcast and post have answered some gardening questions that you have been asking. If you haven’t listened yet, you can hear this episode now by scrolling to the top of the page and clicking the Play icon in the green bar under the page title.
What gardening questions are at the top of your mind this time of year? Let us know in the comments below.
Links & Resources
Some product links in this guide are affiliate links. See full disclosure below.
joegardener Online Gardening Academy™: Popular courses on gardening fundamentals; managing pests, diseases & weeds; seed starting and more.
joegardener Online Gardening Academy Perfect Soil Recipe Master Class: Learn how to create the perfect soil environment for thriving plants.
joegardener Online Gardening Academy Beginning Gardener Fundamentals: Essential principles to know to create a thriving garden.
joegardener Online Gardening Academy Growing Epic Tomatoes: Tomato expert Craig LeHoullier joins me in leading this course on how to grow healthier, productive tomato plants and how to overcome tomato-growing challenges.
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 were 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: Rain Bird, Corona Tools, Milorganite, Soil3, Exmark, Greenhouse Megastore, High Mowing Organic Seeds, Territorial Seed Company, Wild Alaskan Seafood Box and TerraThrive. These companies are either Brand Partners of joegardener.com 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.