308 Q&A Lawn Drainage. Perennial Pruning.

Show Transcript

GB 308 Q&A Lawn Drainage. Perennial Pruning  TRANSCRIPT

24:10

SPEAKERS

Debbie Flower, Farmer Fred, Anita Clevenger

Farmer Fred  00:05

Welcome back to the Tuesday edition of the Garden Basics with Farmer Fred podcast. Unlike the Friday edition, we're dedicating the Tuesday podcast to answering your garden questions. Stay tuned to find out how you can get your garden questions into the program. So come on, let's do this.

Q&A LAWN DRAINAGE TIPS

Farmer Fred  00:25

We like to answer your garden questions here on the Garden Basics podcast. Debbie Flower is herem America's favorite retired college horticultural professor. And if you have a garden question you'd like answered, there's a lot of ways to get them in. You can call or text us at 916-292-8964. You can leave an audio question without making a phone call via speakpipe. Go to speakpipe.com/gardenbasics. E-mail is fine, too. Send it to Fred at farmerfred.com. Or you can fill out the contact box at GardenBasics.net. And you can find the same information in the show notes and in just about every episode as well. So don't write and drive! Thank you very much. All righty. Evan writes us from San Jose, which is south of San Francisco, a very mild climate that used to be an area of a lot of fruit orchards, way back when. Now it's the tech hub with million dollar, two bedroom homes. All right. Go figure. Anyway, Evan writes, "I live in San Jose and in my backyard, I have a very small patch of grass that is around 200 square feet. I want to keep this patch because my daughter practices her gymnastics on it. But in the rainy season, it becomes a swampy bog, so I have to fight the moisture for a few months. During that period, I tend to aerate it with my fork quite a bit. Usually I spend 15 minutes aerating it each week to help it dry out and  de-compact it. I usually only disturb the top four to six inches of the soil. But I'm starting to worry that I'm doing too much. Is it possible to aerate the lawn too much? Can you recommend any non-destructive ways to fight moisture and compaction? On a small lawn?" My first comment to Evan is, if you're using a fork, you're not aerating the soil. You are compacting it.

Debbie Flower  02:17

Yeah, you're creating holes, but pushing the soil to the side which is causing compaction on either side of that. And maybe creating more of a drainage issue. I assume he's having success, or he wouldn't be doing this over and over and over again.

Farmer Fred  02:30

Well, he says it's a fork, but doesn't give details about  the fork.

Debbie Flower  02:35

I'm picturing a garden fork. Yeah. And that's just just tines. Yes, aeration should be done with tubes, hollow tubes that take out a chunk of the soil and whatever roots are in it. And they look if you've ever seen goose poop, what they take out of the hole when they're aerated with a hollow tine aerator looks like goose poop.

Farmer Fred  03:00

Yeah,  if you want to aerate, I still like the idea of renting a power aerator because  as it picks out those cores of soil, the device also eject them on top of the soil. And you want to be able to do that. I think with a hand aerator, it's two motions. You punch down, and then when you bring it back up, you have to eject the cores of soil.

Debbie Flower  03:24

It's a lot of work.

Farmer Fred  03:24

It's a lot of work and Evan, you're working too hard.

Debbie Flower  03:27

Right.  You use a hollow tine aerator of some sort to aerate the soil. Then you want to collect those goose poops, that are about the size of my pinky finger, perhaps three inches long and maybe a quarter to a half an inch across. Then smash them up so that they're just loose soil and then rake them in over the top. Or rake in some sand. Something that would hold those holes open and allow air and water to move through them.

Farmer Fred  03:58

And I guess you could do that with a spreader of some sort. I know that in a lot of situations where you're rehabbing a lawn, and you're dethatching and aerating, that's the other thing you might consider, too,  is dethatching your lawn. But people who have a  rhizomatous... is that a word? Thank you. Rhizomatous or stoloniferous lawn... that can tend to build up a lot of dead material below the surface that you don't ever see, until you bring in a dethatcher. And all of a sudden you've got two cubic yards of dead lawn material  to dispose of. And that can help drainage quite a bit as well.

Debbie Flower  04:39

So those typical grasses that would have that problem are bluegrass, Bermuda grass, and  creeping red fescue.

Farmer Fred  04:49

Yes, that's why it's usually a creeping grass. Exactly.

Debbie Flower  04:53

Yeah, they fill in really well. If you're a golfer. You would love that because it fills in your divots you make but it's a harder grass to maintain because of those stems that crawl across the surface and under the surface of the soil.

Farmer Fred  05:05

Fortunately Evan, it's only 200 square feet. And maybe you can get through what you're calling the aeration process in 15 minutes a week. But I have a funny feeling you're just compacting the soil.

Debbie Flower  05:16

Right. My first question after reading his question is what's causing the flooding? Is the lawn in the lowest part of that  landscape so that water is flowing to it? Is it clay soil, so it just takes a longer time to drain? We're getting more storms that are dropping a lot of rain in a short period of time. And clay soil absorbs water very slowly. So is that the problem? Or is it a perched water table, meaning there are soils with two different types of textures on top of each other, which often happens in new housing developments. That's because  they scrape the land clear, then they build the houses and drive heavy equipment all over the property around the house. And then they bring in, without touching that now compacted soil around the house, they bring in some sort of topsoil mix and throw sod on it. And so you've got the sod, which is always grown in a very loose soil, and then whatever they brought in, which is typically a very loose soil, and then this very compacted soil beneath it. That would slow down water penetration. So if you can figure out what's causing the problem, it's easier to fix it.

Farmer Fred  06:21

One way to do that would be to take out a fairly sizable core of your existing lawn using a flat headed shovel. And make a little square, maybe eight inches by eight inches by eight inches by eight inches, and go down about eight inches, and then bring up that whole block and see what it looks like. Look at the layers.  I wouldn't be surprised that there is this layer of dead stuff right under the green stuff. And then you're going to have loose soil, and then you're going to have the compacted soil, and you want to see  how deep do the roots go? And if the roots are just going around the top because, who wants to go into compacted soil? Okay, well, that might be the issue right there, right.

Debbie Flower  07:02

And the damp season is the time to do it. Because the soil would be easier to dig in. It'll stick together better when you pull it out. So if that's the case, then you've got to create some penetration, some breaks some open spaces between the top of the soil, the stems we're talking about that you would aerate and dethatch to get rid of, and the soil below. So vertical core aeration might fix that as your fork tines only go about four inches deep. So does vertical core aeration, only go four inches deep. If that doesn't do the job. If your soil layers are deeper than that, the compacted one that you need to break open is deeper than that, then you're gonna have to dig holes in places and allow the water to drain there.

Farmer Fred  07:53

Yes, or hardscaping? Yes. Well, there's that.

Debbie Flower  07:56

One other process that may work but it will take years. Golf apparently was invented in Scotland. I am not a golfer. Maybe your wife knows this. But according to my turf professor at UC Davis, Golf was invented in Scotland and the best golf courses were right on the coast. I guess they're called the moors. I'm not positive about that. But the reason they were so good is that the soil was quite well drained. And sand would blow up from the beaches below and basically the sand top dressed the lawns every year, with just a little bit of sand, and that is healthy for a lawn to top dress. There are reasons to do it. Usually the reasons are to either apply nutrition in the form of a compost or composted manure, and to fill in holes. If you've got a lumpy lawn, and you can fill in holes, you can do it every year, you can do it probably twice a year, but you're only applying a quarter to a half an inch of top dress. And the top dress soil needs to be very close to the soil the grass is already growing in. The texture of the two need to match. So you may have to buy topsoil. At a topsoil place, you can mix it up to 1/3 to one half with sand, horticultural sand, and just spread a layer of quarter to half inch over the whole lawn. The grass will grow up into it, it will root into it. And so over time, you're going to raise your lawn, the organic component of what you applied is going to break down, but the sand is going to stay there. So you're gonna raise your lawn maybe a half an inch a year, and you might raise it right up out of that wet spot.

Farmer Fred  09:36

I have, I believe in the past,  written on the Farmer Fred Rant blog page about rehabbing a lawn that included specific instructions on dethatching and aeration, as well as overseeding. And then covering with that top dress material. You can get some good ideas at the soil place on the machinery that makes it a lot easier, like a bigger roller. Actually, you probably want two rollers. If you're overseeding, you got  one that's filled with water to get the seeds down into the soil, and then a rolling cage with small holes that you fill with compost and roll it across the lawn. And it does a very good job. And I have seen those at rental places.  Hey, a good nursery will lend it to you know, for the day. There you go. Yeah, that's the way to do it. But Evan, yeah, if you're doing it every week, for 15 minutes, you're doing it way too much. You throw out a phrase, Debbie of doing it, maybe twice a year. All right. But again, you're removing cores. Unfortunately,  but I'm glad to say we're getting away from this scenario, of when people have a garden problem. They go into a nursery and say, "What can I buy to fix this?" We were at a nursery yesterday. Yes. And we saw a product that I would might think that a an employee who didn't know better or was trying to make a sale might say, "Yeah, we got something we can sell you. It's a natural soil food for lawns and hard soils it it loosens compacted soil that improves root penetration, mass and grass growth and also helps to stimulate microbial life and it's only 30 bucks." And, okay, what's in it? Well, that's a darn fine question. And we were looking at that bag yesterday. I don't think we ever decided what was in it. Or were the ingredients even listed in the back.  I should check my notes on that.

Debbie Flower  11:25

I think it was sulfur and calcium. Yeah. And iron. Yeah, that's what it was. It was micronutrients. Yeah, grass needs those, but it's not going to open your soil. The only kind of soil that this product will have any effect on his sodic soil. That is what it's called. And it's soil with salt in it. There are places where salt and I'm talking like table salt, but there are other salts as well. But tablesalt has sodium in it, where sodium naturally collects in the soil and binds it, making it tight. Calcium can be applied to such soils. And it binds where the sodium is, and releases the sodium and opens up the soil. And typically you apply calcium with sulfur because calcium will greatly change the pH or the alkalinity and acidity of your soil. Sulfur will prevent that from happening with this application. So there's only one very limited situation where this product is going to do anything, other than provide nutrients.

Farmer Fred  12:24

You'd be better off spending your money on a fine compost and rolling that over the lawn. Yes.

Debbie Flower  12:31

And I was saying that this process, the top dressing, can be done twice a year. I wouldn't dethatch and aerate more than once a year. Okay. You want to do the top dressing when the grass is actively growing. I like to topdress  in spring when the forsythia shrubs bloom. That's typically when the soil is warm enough for the spring weed seeds to germinate. And I like to top dress to cover up those baby seedlings so they can't find the sun and they don't grow.

Debbie Flower  12:35

I love horticultural phenology.  And that's what that is. You do garden chores based on what's in bloom  or what's happening in the garden. And the forsythia bloom usually happens in late winter.

Debbie Flower  13:13

Or early spring when the soil is just getting warm enough for things to germinate. Or you find you're mowing the lawn more often.

Farmer Fred  13:21

Yes, there's that too. Again, most lawns, and we don't know what type of lawn Evan has. So it could be a cool season lawn. It could be a warm season lawn. Yes.

Debbie Flower  13:30

And in San Jose, I would guess would be a cool season lawn.

Farmer Fred  13:34

yeah, but you never know.  So, Evan, stay off your lawn.

Debbie Flower  13:39

Yeah, don't walk on it when it's really wet. That compacts the soil in and of itself.

Farmer Fred  13:44

Exactly. Now, it should be moist when you do this work, but not so soggy, not too soggy. That would actually compact the soil. Because when you compact the soil, you're removing air, right? Air is a necessity for root growth.

Debbie Flower  13:56

Yes, it is. Good luck.

Farmer Fred  13:58

There's a lot I would do in this situation, I think. Perhaps start over. Start over, get some professional equipment. I would first of all, I'd dig out that chunk that eight by eight inch chunk.

Debbie Flower  14:09

You got to know what's going on down there. Yeah, identify the pest, if you will. If you do that send us a picture.

Farmer Fred  14:16

Yeah, it could be the thatch layer that needs to get removed, if you see a layer of dead stuff below the green stuff before it hits soil. If, on the other hand, when you dig that out and it's just dripping water, well, then you've got a watering issue. That could be the flow from your neighbor's sprinklers or your own sprinklers. And it just may be as you said, Debbie, just a low lying area. But if it's supporting a lawn, lawns are amazingly resilient.

Debbie Flower  14:44

They are. That's why people like them. You only have to know one set of instructions to care for a lawn. Yes. Yeah, I suspect there's layers of soil in there that are impeding water flow. And if it smells, you really got a problem. Yes, it smells like low tide. Or dead fish.

Farmer Fred  15:01

Yeah, that means your soil is getting way too much water. And so think about where the water is coming from and how much you're watering. It sounds like maybe you can turn off the sprinklers, if that's the issue.

Debbie Flower  15:13

Yeah. And maybe your daughter needs a really nice mat or trampoline..

Farmer Fred  15:18

Yeah, we don't want to discourage your daughter, Evan, from practicing her gymnastics. But yeah, a mat. That makes sense, a 200 square foot mat. right? Yeah. And you'd save yourself a lot of work, it would be a worthwhile investment, right?

Debbie Flower  15:32

And then, when she's done, or moved on, you can raise that soil level and have a lawn or whatever you want to grow in that location.

Farmer Fred  15:41

Or, you can leave the mat there and sleep out there at night because your wife kicked you out. So  there's always that. All right, so good luck with improving your lawn drainage there, Evan. Thanks for writing in to the Garden Basics podcast, and thank you, Debbie.

Debbie Flower  15:54

You're welcome, Fred.

Q&A SOURCES FOR PRUNING, PROTECTING PERENNIALS

Farmer Fred  16:02

We're talking with Anita Clevenger. Here in the perennial plant section at the Fair Oaks Horticulture Center. And Steve from Granite Bay, which is in Placer.County, just a little north of Sacramento writes in and says, "I enjoy your podcast and presentations. Who would you recommend I contact with specific questions regarding my perennials? I tried online searches at ucanr.edu, and local garden centers, but received varying answers. And this time of year I'm putting together frost sensitive lists and pruning lists of when and how much. I would appreciate any guidance you can provide." Anita, since we're both Master Gardeners with UC, at least we know the research UC does is verified.

Anita Clevenger  16:42

Yes, it is. And this demonstration garden that we're standing in the midst of, at the Fair Oaks Horticulture Center, has many plants that UC recommends, they have their list of all-star plants that are good for Valley gardening, and we display many of them. The first thing that we look at for resources is the UC resources. We create some of our own for example, we have a garden note on grasses, and how to cut them back. And we have lists of what the plants are that we have here. And each plant that is out here has a label so you can see how it grows, you can see how we take care of it. And you can look it up online if you want further information. One of the advantages to the water efficient landscape is it is open 365 days a year from dawn to dusk. And so you can always walk through and observe what is happening here. During our open garden days, when the entire Horticulture Center is open, you can also talk to people like me about what we do.

Farmer Fred  17:46

And that would include pruning information, frost sensitive information, the timing, the best time of year to do things. In fact, if you make a regular habit of coming out here, like on a monthly basis, you can get a pretty good idea of what you should be doing in your garden every month.

Anita Clevenger  17:59

That's correct. And basically with perennials and grasses, a lot of the cutback is in February or March. You wait until the risk of freeze is gone. You allow some vegetation to stay for beneficial insects to overwinter in. But then come spring, you want to clear things up and promote new growth. And so as a general rule of thumb, that's a lot of what we do. And I do want to mention there is a Sacramento Perennial Plant club,  that meets down at McKinley Park at the Shepherd Garden and Arts Center. So it is a city centered place, but we have members from everywhere, and speakers from everywhere. And that is a great group to get that sort of advice from.

Farmer Fred  18:42

And Steve is in Granite Bay,  a pretty close drive to both the Fairoaks Hort Center as well as the Shepherd Garden and Arts Center. But wherever you live, and you're looking for information about how to grow plants, you probably have a local Cooperative Extension Master Gardener organization, or you have local garden clubs that you can get some pretty good information from. And I still like books. Such as the Sunset Western garden book for general plant information, and they usually have information on each plant about when to prune and their frost sensitivity. But if you want more details about pruning, one book I really like is the Pruning and Training book that is produced by the American Horticulture Society which contains more plants than you could ever think about and what they exactly need in the way of pruning and training. You know, you mentioned something that ticks me off when I see it this time of year. We're now in early February, and I see people cutting back their ornamental grasses, and I'm thinking. "oh, those poor lady bugs that are probably spending the winter in there that are going to be exposed to more cold weather". And as you pointed out, ornamental grasses are best cut back after all danger of frost.

Anita Clevenger  19:49

And again, the overwintering aspect for the insects as well as the beautiful plumes of the dried grasses. This Time of year provides much more interest and movement in the garden than you generally have. So when you cut them back, you just have these little bare spots. And so I like to keep them both for appearance as well as for environmental reasons. But there are warm season grasses that start to grow when the weather gets warm,  hence the name. And so you don't want to wait too long, because you'll be taking  off the growing tips. So it's a matter of timing. And so we used to prune the grasses earlier. We are now thinking perhaps February or early March is  soon enough.

Farmer Fred  20:36

Yeah, it depends on when your threat of last frost is. It seems to be changing around here. It used to be like March 15, that would be a good date for last frost here in our area. And now people are saying, maybe it's early February. But then again, we just had a frost two days ago.

Anita Clevenger  20:54

Yes, that's correct. But it isn't so much the frost that might damage the grasses, it is the habitat. And the beauty of them. One of the reasons you plant them is for the dried flower heads.

Farmer Fred  21:06

I like to wait to prune ornamental grasses until I see the ladybugs start emerging. And that's usually on a warm day in late winter that you'll start seeing them coming out. And then I think once you see that, you can probably go ahead and prune it back.

Anita Clevenger  21:20

That's good advice and a lot easier to do at your own home where you're seeing it every day. We come out here and work a couple times a month. And so we do try to schedule things. And because we do, you can come out and talk to us. We can tell you what schedule we use.

Farmer Fred  21:35

Take advantage of your local university garden department. Land grant universities always have either a farm or garden department. And you'd be surprised at the number of Master Gardener outlets throughout the country, as well as just good advice that they would have online. So in any sort of internet search on plants or pest problems, it always helps to put in the name of the bug that's bothering you, let's say aphids, and then type in, ".edu." And that way, usually, the first page of results you get are going to be from universities where there's probably some peer review going on that ascertains the veracity of whatever advice is being given.

Anita Clevenger  22:13

That's correct. Definitely the first place I look for everything is the UC sites. That's because we are in California. That's correct. Yes, but for my family in Ohio, I tell them to look at Ohio State.

Farmer Fred  22:25

Exactly. Well,  that's what to do about perennials and figuring out when to prune them and when to protect them. It's Anita Clevenger, Sacramento County Master Gardener Thank you, Anita.

Anita Clevenger  22:36

Oh, you're welcome Fred.

Farmer Fred  22:46

Want to leave us a garden question? You'll find a link at Gardenbasics.net. Also, when you click on any episode at GardenBasics.net, you're going to find a link to Speakpipe. You'll find it in the show notes. And when you bring up SpeakPipe on your computer or smartphone, you can leave us an audio question without making a phone call. You can go to our page on Speakpipe directly, speakpipe.com/garden basics. You want to call or text us? We have that number posted at GardenBasics.net . Ii's 916-292-8964, 916-292-8964. Email ? Sure, we like email! Send it along with your pictures to Fred at farmerfred.com. Or again go to garden basics.net and get that link. And if you send us a question, be sure to tell us where you're gardening because all gardening is local. Find it all at Gardenbasics.net

Farmer Fred  23:45

Garden Basics with Farmer Fred comes out every Tuesday and Friday and it's brought to you by Smart Pots and Dave Wilson nursery. Garden Basics. It's available wherever podcasts are handed out. For more information about the podcast, visit our website gardenbasics.net . And that's where you can find out about the free Garden Basics newsletter, Beyond the Basics. And thank you so much for listening!