Between my podcast listeners and members of my e-newsletter and social media channels, I receive a lot of gardening questions. This week, I’m highlighting questions asked by students of my new Beginning Gardener Fundamentals course. I introduced the course at the beginning of this year to teach the fundamental garden basics I’m asked all the time and because I often heard requests for this type of teaching tool.
The first class of students have loved the course, and they’ve been asking great follow-up questions on both the course platform and the students-only Facebook group, where I’ve been holding twice-weekly live Q&A sessions. It has been amazing to interact one-on-one and to hear the excitement build as students gear up for their best growing season ever!
Erin, my Director of Online Media, joined me this week to call out some student questions which we thought would be interesting and helpful for other gardeners. Although the questions, themselves, are specific; they offer some valuable lessons that may help you this year too. So, let’s get started.
Soil
You probably won’t be surprised to learn that my online course included a lot of information on soil – how to achieve really healthy soil and why it matters. After all, one of my mottos is “Feed the soil, and let your soil feed the plants.” It’s the foundation of a thriving garden.
Student Loneva B. began applying what she learned almost immediately. During one of our Q&A sessions, Loneva explained that she had purchased bags of garden “soil” online just prior to taking the course. When it arrived, she realized the bags were 100% peat-moss based formula with a slow-release fertilizer. The product was so lightweight (and ship-able), because the peat moss was completely dry.
Since taking the course, Loneva realized this product was not a good option for her garden, so she purchased high-quality soil, scrutinizing the ingredients based on my recommendations. Now to Loneva’s question: She wanted to know if she could mix the peat moss product in with the good garden soil. She was stuck with it, so could she put it to use?
Soil is the foundation of a healthy garden, so don’t skimp. Pay attention to the ingredients which make up any soil product you purchase.
I don’t think I’ve ever mentioned this, but I love to buy online. However, one thing I’m not a proponent of buying online is soil. For one thing, there are nearly always plenty of great options locally. For another, soil should be heavy, which means it’s not easy – and certainly wouldn’t be cheap – to ship.
Good garden soil should include materials such as composted wood products and composted manure. Perlite and vermiculite are common ingredients as well, because they do a good job of retaining moisture while also allowing plant roots to breathe.
No matter where you buy soil, check the ingredients. If you buy in bulk – which can often be a more cost-efficient option – don’t be shy about asking for details on the ingredients. Be an informed consumer. Another benefit to buying locally is that you can see and feel the soil to get a better idea of the quality of the product.
All that said, if you do make a mistake and find yourself stuck with a poor soil product, you can still make use of it by adding it in small percentages to a high-quality product. But before you do, learn a little about the ingredients.
Peat moss, for example, is acidic, so it can lower the pH of your soil. However, the biggest drawback to peat moss in soil is its resistance to re-hydration. Although it’s a common ingredient in potting soil – intended for container gardening – and known for water retention, it can become nearly impervious to water if it’s allowed to dry out.
The moral of the story is definitely to pay attention to what’s in any soil you purchase. If you have $10 to spend on the garden, put $9 of it toward your soil. That investment will pay off every time.
The same is true if you garden in containers. Gretchen B is a container gardener and, like plenty of students, she’s very focused on her soil after having gone through the course. Last year, she didn’t use fresh soil in her containers, and she experienced drainage issues which caused her plants to suffer. So, Gretchen wanted to know if the drainage problem was due to re-using the soil and if there is a way to re-use container soil.
Potting soil is designed for containers, and it’s hard to find any potting soil product without some added nutrients. Containers require such frequent watering that nutrients leach out quickly. You can and should be providing supplemental nutrients through the season, but potting soil which has languished over the winter will need a little more help.
Before you plant, remove the used soil from the container. Dump it out and re-introduce some quality fresh ingredients, like compost, finely ground pine bark, vermiculite, perlite, and some slow-release nutrients. Fluff the soil back up with these added ingredients, then it’s ready to be re-used. It takes a little time and might cost a little more, but the results will be worth it.
During the course of the season, container soil becomes compacted, so if you don’t fluff it and replenish some of the organic matter, odds are good that poor drainage will be an issue. For peak performance, you need to refresh or invest in new potting soil every season.
If you choose to use new potting soil and you have garden beds, you can add the used soil to the garden. Any remaining organic matter – like old plant roots – will break down and improve your garden soil over time.
If you re-use container soil year after year, be sure to refresh it with quality amendments. Otherwise, it can become compacted and depleted of the nutrients your plants will need to bloom and fruit.
Mulch
Student, Sandra G., began to really think through her approach to composting and mulch after going through the course. Last fall, she collected several barrels worth of leaves and has been storing them in an open container, adding handfuls to her compost pile as “brown” material to offset her “green” compost inputs. After several weeks went by, she noticed a leaf compost “tea” leaking out of her leaf containers.
That got her garden curiosity going. She wanted to know the best use for her leaves. Should she:
- Encourage them to decompose faster and use them as mulch to feed the soil around her plants (along with the “tea)?
- Continue to save them for the compost pile – as a “brown” material to offset the plentiful “green” materials which become more abundant through the summer?
To that I say, there is no better option here. Get your hands on as many leaves as you can in the fall and use them as mulch and in your compost. They are a great source of nutrients and carbon. The “tea” that Sandra noticed is just the natural decomposition of the leaves, and there’s a bit of nutritional value in that too.
I can’t say often enough how much I love leaves in the garden. When you grind them up or shred them to use as mulch; they look good, stay in place, and break down to improve the health of your soil. And who doesn’t love that leaves are free?
Leaves added to your compost will infuse it with lots of nutrients, which will improve your soil when you amend with the finished compost.
Whether you use leaves in mulch or in compost – or both – you just can’t go wrong.
Student Stephanie M. mulches her garden with shredded hardwood and pine straw. Before she direct-sows flower seeds, she pulls the mulch back from the soil to encourage the surface to warm more quickly. In past seasons, she has lightly spread mulch back over the soil surface to protect it from rain erosion or becoming too dry.
After going through the course, she wanted to know if that was the right approach.
I’m a huge proponent of mulch and teach a lot about the benefits it offers throughout the landscape. It’s so important to protect the surface of your soil – for many reasons.
However, most seeds germinate so quickly that I don’t mulch over them. Because they require moist soil, I’ll be watering diligently, so the soil surface won’t have the opportunity to crust over. There is a slight risk of erosion from rain, but for me, that’s offset by the seeds’ need for sunlight. The seedling needs to be able to break the soil surface without using more energy to push through a layer of mulch.
For seeds which take more than a week or so to germinate (like carrots), I will sprinkle the soil surface very lightly with grass clippings. Other mulch materials are just too thick or heavy (or both) and could block the emerging seedlings.
As for any weeds which might sprout in the exposed soil, they’ll be easy to remove while I’m checking on the progress of my growing seedlings. All in all, I wait to add mulch until the seedlings are well on their way.
Shredded or ground up leaves are an amazing benefit to your garden – whether you add them to your compost pile or use them as mulch.
Seeds and Seedlings
Speaking of seeds, I’ve been big on starting seeds indoors during the past two years. It’s a project I’ve always done, but I’ve taken things to another level to help my daughter start a business and develop a love of gardening. I’ve also experimented to observe how seedlings respond to all sorts of different variables, and I shared results and tips on my Instagram and Facebook page.
Many students started seeds indoors too and had lots of good questions through the early months. Theresa P. had a question which applies to starting indoors or direct sowing outdoors: Are the “days to harvest” indicated on seed packages accurate?
Well, some seed packets provide a very precise number of days to maturity or days to harvest. Consider that a guideline, but don’t expect your crop to be ready after that precise time period. There are just too many variables which will impact growth.
Will your weather cooperate? How healthy is your soil? How fresh are the seeds? Nature can be a fickle business.
That said, the approximate number of days to maturity is fairly accurate, but it’s important to understand that the time period relates to when you sow the seed outdoors – or when you plant the seedling outdoors.
Is the seed recommended for direct sowing or for starting indoors? It’s recommended that Bok choy, for example, be direct sown. The days to maturity on a seed packet for bok choy will accurately tell you the approximate number of days which will pass before you can start to harvest leaves.
On the other hand, a tomato seed packet might indicate something like “70 days to harvest.” It’s always recommended that tomato seeds be started indoors 8-10 weeks before the last frost. So, think that through. It will be 60-70 days before you are even able to get that seedling into the ground, right? You certainly won’t be enjoying any tomato fruit right after you put the plant into the garden.
It will take another 70 days after the time you’ve planted your seedling into the ground before you’ll have ripe tomatoes. So again, the “70 days to harvest” on the package relates to the length of wait after the seedling goes into the ground.
Here’s one more example to drive that point home: It’s recommended that you plant beet seeds outdoors. If the seed packet indicates 45 days to harvest, that’s based on when the seed is sown outdoors – as recommended.
Well what if, like me, you start your beet seeds indoors? In that case, regardless of when I place the beet seedlings into the ground, I’ll still be harvesting beets approximately 45 days after I sowed the seeds. Why? Because the maturity date is based on the assumption that I’ve followed recommendations and direct sown them outdoors.
Never be afraid to experiment outside the boundaries of recommendation.
The days to maturity indicated on a seed packet are a good guideline, based on when the seed or seedling is put into the ground.
Belinda G. asked another good seedling question during a Facebook Q&A session. She wanted to know whether or not there is a general rule for pinching back seedlings once they’ve been placed into the ground. Do the basic principles apply for both edible plants and ornamentals?
The purpose of pinching back is to encourage the plant to become more compact or bushy (or both). Flowers tend to respond well to pinching and fleshy edibles like basil and pepper plants can be pinched back too.
So, what is pinching, exactly? Start from the top of the plant and move down the stem, looking for pairs of leaves (also known as leaf nodes). Ideally, you’ll pinch off the stem at the first or second leaf node from the top. You literally pinch the stem between your thumb and forefinger just above the node to clip off the stem. This stimulates the plant to create new branches where you’ve pinched, creating a fuller plant.
It’s possible to get too aggressive here. If your plant is only a few nodes tall – or if you pinch too many nodes down from the top – you may be removing too much foliage. It’s much more important that the plant have enough foliage to generate energy from the sun to grow those roots out than it is to pinch at all.
Pinching is not a necessity for a healthy plant. As the temperatures warm and the young plant becomes more established, it will become naturally full.
On the other hand, pinching flowers off of young, establishing plants can really be beneficial. It’s common for edible plants to want to fruit too early. Pinching off the flowers (or any immature fruit) while the plant is settling into your garden will force the plant to focus its energy on root development. That way, it will be better prepared to provide a bountiful crop.
So when you’re buying seedlings, don’t make the mistake of opting for the flowering plant. There’s nothing wrong with that choice, but your plant will be better off if you pinch off any flowers once you get it home and into the ground or your container.
When should you stop pinching flowers? I’ve agonized over a good answer to that question, but the fact is, there is no definitive answer. It’s a touch-and-feel thing.
I’ve gardened long enough to recognize when my plants are large, mature and established enough to handle fruiting. This is a judgement call for every gardener, so again, don’t be afraid to experiment. Try different timing, see what happens and make notes for next season. There’s no wrong answer.
Here’s another edible seedling tip that many gardeners don’t realize: The tiny white fibers all along the stem of a tomato plant will become roots when buried in soil. So, you will have a healthier, hardier plant if you bury the seedling deeply – very deeply. I recommend burying them up to just a few leaf nodes from the top.
This approach doesn’t work with other edible plants – at least not to such an extreme. However, I do plant other edibles deeper than their starter pot soil level. How much deeper? I’ll often bury half the stem of vegetables like peppers and eggplant.
I encourage you to give that a try. After all, what’s the worst that can happen? If you lose the plant, it’s not a big investment, but the experiment will teach you a lot that you can implement in your garden for years to come. So much of good gardening is all about trial and error – and keeping notes of what you’ve learned.
When I planted these tomatoes, I buried most of the stem too. The tiny white fibers all along the stem will turn to roots, and that’s one of the reasons my tomatoes become so robust and healthy.
Garden Organization
I’m a big proponent of taking notes and capturing pictures throughout the year and as you spend time with your plants in the garden. Student Belinda G. began using the DayOne app for her note taking this year. It’s my favorite method for gathering all kinds of garden observations. I also love that I can dictate what I see, and the app will convert the audible information into a searchable notes format. I can also attach images and scanned documents too.
Belinda wanted to know some specifics – what type of information I record and my recommendations.
The thing is, I document a lot of information. I figure it’s better to have it and not need it than to need it and not have it. Sometimes a few years might pass before I see something that i think I’ve seen before. The notes in my DayOne journal give me the opportunity to search and find what I’m looking for.
Each gardener will have different needs. When you’re keeping a garden journal, whether in an app or a notebook, it’s your garden; so keep track of what matters to you. You may be particularly fond of butterflies and find a lot of value from noting butterfly observations, while another gardener may be more focused on a beloved plant variety.
The bottom line is, take a lot of pictures and if you wonder whether something you notice is worth recording, it probably is. I especially recommend taking notes of anything unique, exceptions which stand out in the garden. The notes will help you to remember what you did (or didn’t do) and how the plant responded, so that you can re-create your success (or avoid a mistake).
This year, I made a lot of notes about the tomato seedlings I started indoors. I recorded my watering details, lighting height and duration, supplemental nutrients, and many other details. Next year, I’ll adjust and record the results again to be able to compare the results from both seasons.
It may sound garden-geeky, but these are the things that will really help you “up your game” in the garden.
While plants are very young and still getting established, pinching off the flowers on various types of crops such as tomatoes and peppers will redirect the plant to focus on root development and overall establishment first. These cucumbers are well-settled in and as a result, are ready to start making fruit as you can see from the flowers on the left.
Diagnosis
Observation is a very powerful tool for diagnosing garden problems. Determining the cause behind plant issues can be tricky, so take a step back and think things through. Be a Sherlock Holmes in your garden. Assess the crime scene. That’s how I helped Kathleen S. to pinpoint a likely culprit.
Oftentimes students will post a photo with their question, and that’s what Kathleen did when she had trouble with some of her tomato plants. She shared a couple photos to ask what might cause them to look so faded and unhealthy.
Photos can be really helpful, and in this case, I noticed brown spots on the leaves and immediately suspected disease.
Kathleen had just put in new soil, so she suspected the problem was soil-related. That’s a natural conclusion, however there were other plants in the same bed which were healthy.
I also learned (after a little back and forth in the Q&A session) that the unhealthy plants were of just one variety, and she’d gifted some to her mother. Guess what? Her mother’s plants were faded and spotted too.
All of those factors pointed to the problem being unique to the one plant variety – not the soil or the surroundings. So, what’s left? The likely culprit is the seed itself. Since no other tomato varieties in Kathleen’s garden were impacted, odds are good that there was disease within the seed. I recommended that she reach out to the seed supplier to ask if the batch number (seed packets usually include a batch number) had potentially been diseased.
If your dealing with a garden problem, think about what is unique relative to everything else in the space. Is it a single plant, a single bed, or a single water source? When you find what’s unique, you’ll find your best place to start to solve the issue.
I hope these questions have gotten you thinking about your gardening in a different way. There are lots of factors at work out there and so many things to learn. You can scroll to the top of the page and click the Play icon in the green bar under the page title to hear my fun conversation with Erin, as we revisited these questions from some curious gardeners. I’m so excited to watch the progress in my Beginning Gardener Fundamental students’ gardens! And I encourage you to share stories of your progress too – in the Comments section below.
When you observe an issue with a plant (or plants) in your garden, put on your detective hat. Consider what is unique to the affected area to guide you to the cause of the problem. In this case, it wasn’t a disease at all on these tomato leaves. It was sun-scald during the hardening-off process. Asking lots of questions will usually get you to the source of the problem.
Links & Resources
Episode 046: Organizing Your Gardening Life
Episode 063: Garden Fertilizer Basics: What to Know Before You Grow
joegardenerTV YouTube: The Best Ways to Plant a Tomato
joegardenerTV YouTube: Starting Beet Seeds in Containers for Better Results
Beginning Gardener Fundamentals – Online course details
Beginning Gardener Fundamentals – Registration wait list: Sign up to be notified about the next class!
Growing a Greener World® Episode 904 – Waking Up the GardenFarm™
Milorganite® – Our podcast episode sponsor and Brand Partner of joegardener.com
Pete and Gerry’s Organic Eggs – Podcast episode sponsor and Brand Partner of joegardener.com
0 Responses to “105-Gardening Questions Answered: Expert Advice from Joe Lamp’l”
Once again, Joe Lamp’l, you kept me company yesterday with the greenhouse podcast (ph wouldn’t connect for comment) while I planted peas. Today, we’re hauling dirt and we’re not done so I’ll find another pod in a min. DayOne downloaded. I just love listening to these – they’re all so relevant! Thanks, Joe! ❤️
Thanks Denise. I love hearing this. Thanks for letting me keep you company.