Two Cheap Tools That Will Make You a Better Gardener
- Diana Pierce
- 4 days ago
- 7 min read
By Diana Pierce | May 20, 2026
When Mary Lahr Schier tells you it’s time to plant, you plant.
When she tells you to wait, you wait.
And when she says you need tools? You get them.
Remember the old E.F. Hutton ads? When Mary talks, gardeners listen.
The longtime editor of Northern Gardener magazine and author of The Northern Gardener: From Apples to Zinnias (Minnesota Historical Society Press, 2017), she has spent decades helping gardeners navigate the particular joys and frustrations of gardening in a state that keeps you humble.
We sat down recently, right in that hopeful window when the garden centers are bursting and the impulse to plant everything is strong.
Mary was clear about what’s ready, what isn’t, and why the cheap tools matter more than the expensive ones.
What Goes In Now (And What Waits)
Diana: What flowers, vegetables, and herbs are safe for most gardeners to plant right now? And what should we wait just a little bit longer for?
Mary: To start with, I think there are two tools every gardener should have right now and both cheap. A rain gauge (Mary’s) and a soil thermometer (Mary’s). If you have a soil thermometer, you can check your own garden. You might find the soil is only 40 degrees. Yes, you could plant seeds, but they’re not going to germinate. The threshold for most warm-season vegetables is about 60 degrees. Below that, seeds like green beans, squash, and melons will just sit there. They’ll germinate eventually, but they won’t really get going.
Diana’s Note: See Mary’s chart for soil temps and plants.
Mary: Second, right now there’s quite a lot that can go in - more than people might think. Most annuals are ready, and not just the cold-weather standbys like pansies. Petunias, snapdragons, Osteospermum, these can handle temperatures down into the 40s, and with lows forecast above 44 degrees for the next couple of weeks, the timing is good.
Trees, shrubs, and perennials? Go right ahead. Anything that’s hardy to our zone, put it out there. They’ll be fine.
For tender tropicals like caladiums and mandevillas, I’m cautious but practical. I have my own mandevillas outside already, but I can bring them in. If you can put them out during the day so they get all the benefits of the sun, but bring them in if it’s a cold night, then it’s probably okay to put them out.
I live in a townhouse, so I grow a lot on a deck. I put my containers on rollers so I can slide them into the sunroom if we get a cold night.
Tomatoes and peppers I would hold until Memorial Day. You could use Wall O’ Waters or a hoop house, but even then you still might want to pause. I was at a friend’s house the other day and her tomatoes with Wall O’ Waters around them did not look very happy.
My tomatoes spend their nights in the basement at 68 degrees and they look great. Wait on those.
Are We Already Too Dry?
Diana: Because we had such a dry winter and limited snow cover, are we already too dry? What concerns are you seeing in Minnesota gardens this spring?
Mary: We’re slightly dry. But I want to be precise about it. Normally by this time of year, the Twin Cities has accumulated about eight inches of precipitation. Right now we’re sitting somewhere between five and six. That’s a gap, but it’s not a crisis. Not here, anyway.
Diana’s Note: Mary uses a 30-day map. You can also see a DNR drought monitor map where you can check your city. This shows the U-S map.
Mary: However, If you go down to the southwestern corner of the state (Rock and Pipestone Counties), near the Luverne area, that’s our agricultural heartland, and they’re technically in a moderate-plus drought. They’re quite dry. But the Twin Cities corridor down to Rochester, up through St. Cloud is not technically in a drought. Just a little parched.
What that means: pay attention to newly planted trees. An arborist I knew in Northfield taught me this — water new trees every single day for the first two to three weeks. Not a lot, but every day. Then every other day. And always with an eye on the rain gauge. If you’ve got a half-inch of rain, you’re good, you don’t have to do anything.
I keep two rain gauges, both cheap plastic. One on my deck, one at my community garden three miles away. Those two spots are only three miles apart but they often get completely different amounts of rain. With Minnesota thunderstorms, you can get an inch in one backyard and nothing in the next.
Stop Worrying. Start Planting.
Diana: What do you think gardeners are worrying about right now that they really don’t need to worry about?
Mary: Invasives, a little — though there’s so much information out there right now, good and bad, that it’s genuinely hard for people to sort through what’s correct. That’s a real challenge.
Light is another one. People worry a lot about whether they have the right light, and you should think about it. But don’t let it stop you. My townhome has a north-facing side with terrible light. I put my hardiest hydrangeas there as an experiment. They are the paniculatas and other Minnesota-tough varieties. They’re doing beautifully. Definitely less light than they should have, but they’re happy and I’m happy. My neighbor gets to look at them. I never even see them but she enjoys them.
Plants will survive. If they have ideal light they’ll thrive and go crazy. If they have a little less, they might not bloom quite as much. But they might still be something you really enjoy. Try it and see.
Container combinations are another thing people overthink. They ask what would look good together and honestly, most things look good together. The sparse one will fill in. The full one, something will dominate and the other stuff will fade. That’s just what happens.
The Finger Test (And Why Overwatering Kills More Plants Than Drought)
Diana: Many people think the spring rains will take care of their gardens. What are some tips for knowing when plants actually need water, especially in containers, and how do we keep from overwatering?
Mary: I do the finger test. Stick your finger in the soil to just past the second knuckle. If it’s dry down that far, it’s probably time to water. And when plants start to struggle, the first thing I ask is: how much have you been watering? Because it’s more often overwatering than underwatering.
A lot depends on your potting mix. Well-draining mixes mean you’ll water more. Mixes with good water retention — peat, coir, or other amendments — hold moisture longer. The tricky part is that potting mixes have changed a lot in recent years. Peat-based mixes have given way to alternatives with coconut coir, hydrolyzed wood, all sorts of things that behave differently. You have to test to see how well yours drains and how quickly it dries out.
Diana’s Note: Mary is testing a potting mix called Pittmoss, made from paper fiber and it has very different water retention. She's using it blended with other mixes. This is what she wrote about it - https://maryschier.substack.com/p/is-pittmoss-the-new-peat-moss
Mary: Wind is the other big factor that surprises people. When it’s windy like it’s been lately, that just pulls the water out of everything. A container in a south-facing, wind-exposed spot can dry out faster than you’d expect even after a thorough soaking.
Go In With a List. Seriously.
Diana: Do you see people panic-buying or overdoing it at this time of year?
Mary: I’m sending you a picture of what my sunroom looks like right now.
I’ve overbought. I got a shipping notice this morning for shrubs I’d completely forgotten I ordered.
I think people do overbuy. You get into the nursery and it’s all so beautiful. But plants have gotten more expensive, so it helps to go in with a list. Think through what your pots are going to be ahead of time. This is a case of do as I say, not as I do. I get in there and I have a cart full before I know it. The checklist I try to keep in mind: is it right for your light, more or less, and do you have a place to put it?
Before You Hit the Sales
Diana: As we head into garden club and Master Gardener sales right now, what should we consider?
Mary: Keep the list. Think about holes in your existing plantings. But don’t make that call too early. Some things do come up late, and we haven’t had an excessively warm spring. It’s been average to a little cool. Let things fill in and then decide where the holes are.
Also keep in mind that for commercial retailers, the first three weekends of May are everything. They make a huge portion of their money in that one short window. A beautiful weekend is a gift for them. A cold, rainy one is a real bummer.
The Most Important Thing You Can Do Right Now
Diana: What’s one piece of advice you wish every Minnesota gardener would think about this time of year?
Mary: Pay attention to your soil. If you have garden beds, this is a good time to put down a light layer of compost. It’s important to feed the soil itself. If you’re doing containers, I save my potting mix from year to year, but I never reuse just the old stuff. I always blend in some fresh mix, compost, or something else. You’re setting yourself up for a good season. And for vegetable gardening especially, lay down some compost now. Some people do it in the fall, but if you didn’t, now is a great time. Get your soil right and the plants will do the rest.
You can find Mary on SubStack -https://maryschier.substack.com
Mary is also the author of The Northern Gardener: From Apples to Zinnias (Minnesota Historical Society Press, 2017) and the former editor of Northern Gardener magazine.
Happy Planting!
Diana
© 2026 Diana Pierce
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