320 Q&A Citrus, Cats, Tomatoes

Garden Basics with Farmer Fred

Tips for beginning and experienced gardeners. New, 30-minute (or less) episodes arrive every Tuesday and Friday. Fred Hoffman has been a U.C. Certifi...

Show Notes

Questions from listeners include:
Why Your Citrus Tree Leaves May Be Yellowing (at 00:24 of podcast)
Cat-Proofing Your Raised Bed Garden (13:03)
Good Tomato Seed Sources (17:44)

Previous episodes, show notes, links, product information, and transcripts at the home site for Garden Basics with Farmer Fred, GardenBasics.net. Transcripts and episode chapters also available at Buzzsprout.

Pictured:  The Citrus Grove at the Fair Oaks Horticulture Center

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Smart Pots https://smartpots.com/fred/
Dave Wilson Nursery https://www.davewilson.com/home-garden/

Diagnosing Citrus Diseases and Deficiencies via Leaf Color (UCANR)

Sacramento County Master Gardener Website

Harvest Day at the Fair Oaks Horticulture Center

Dan Vierria’s Sac Co Master Gardeners’ Tomato Variety List

Totally Tomatoes
Tomato Growers Supply Co
Burpee Seeds
Baker Creek Heirloom Seeds
Tomato Fest
Seeds ’n Such

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Show Transcript

GB 320 TRANSCRIPT Q&A Citrus, Cats, Tomatoes



Farmer Fred  0:05

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 question in to the program. So come on, let's do this.




Farmer Fred

We like to get your garden questions answered here at the garden basics podcast. We get a lot of questions this time of year about yellowing leaves on citrus trees.

And we get one from John who writes in and says, “I have several citrus trees going. But this grapefruit tree we planted last year has had yellow leaves from the get go. And no matter what I try, they stay that way. I fertilize all my citrus and the other established trees and they love it. I've got a navel orange, a Satsuma, a lemon, and an Oro Blanco grapefruit. There’s  a kumquat next to this one, and a new Mandarin, further up the hill, that are getting a couple of yellow leaves. Also I dug up one and the roots didn't look too good. There was still sawdust packed in it, so I shook it out and replanted it into a pot. A few days ago, in desperation, I mixed in more citrus fertilizer into the soil before planting and used some bat guano fertilizer to see if that helps. And I also cut back the top a little. Do you have any ideas?”

Well, John, you might be loving that citrus tree to death. But there's a lot of other extenuating circumstances here that we need to get into. We're talking with Master Gardener JaNahn Scalapino, here at the fair oaks Horticulture Center on a workshop day. Yellowing citrus leaves, JaNahn. And we're standing right next to the row of citrus we have here and  some of them do have yellow leaves. And in some cases, that's just the nature of the tree. But there is several reasons why citrus trees can get yellow leaves, even in late winter.


JaNahn Scalapino  1:54

Especially in the winter. The cold weather inhibits uptake of nutrients, so the leaves are a little bit deficient in nitrogen and iron. But as the weather warms up, the trees will respond by increasing their uptake of the nutrients that are already in the soil and they will green up many times. I will say that a little iron and sometimes nitrogen are helpful even in older trees. We like to fertilize young trees starting in early March or so with an approved citrus fertilizer. Or you can cobble together your favorite organic compounds if you would like; but the trees don't really care. Sometimes watering will have a direct effect on yellowing of the leaves. Too much water, especially through the winter, can certainly yellow leafs and some of that you can't help, if you don't have good drainage.

But certainly we don't water much during the winter at all.

As the weather warms up again, we may start to water. Depending on the temperatures we may start to water in late April or May; certainly by June we are watering. Usually weekly is best for citrus. They like to be deeply watered and not shallow watered. We also like to have our citrus in their own area (specified plots), with a nice thick layer of mulch. We don't like to see citrus planted in lawns with a narrow little clear area around the trunk. They're susceptible to lawnmower damage and weed trimmer damage. And the water doesn't penetrate down through the lawn very well. We like to have a big clear area around the drip line, if you're going to plant citrus at home. Finally, there are certain nutrients that can contribute to curling of the leaves and yellowing of the leaves like manganese, magnesium, and potassium. You can find publications that will show deficiencies, and you can puzzle out what your particular soil might be deficient in and gently replace some of that. Or you can bring pictures of your tree and even samples in to see us at an open garden out here at the Fair Oaks horticultural center. And we can look at pictures with you and look at what you brought in and maybe figure out if there's a deficiency. Finally, what Farmer Fred said about the trees, some being a bit yellower than others, a lighter green yellow, is also true. It's a variety thing.

That question about the yellow leaves from the get go, man, that makes me worry that the plant that came from the nursery or wherever, might just not have been the healthiest specimen. So that anything that you have done is not going to fix it. And I wonder if you should consider starting with a new plant.


Farmer Fred  5:18

There's a lot of things we can consider in this. But let's talk about what you're doing right with citrus out here at the Fair Oaks Horticulture Center. First of all, it's on a slope. So water is not going to puddle beneath these trees, it's going to keep flowing. So you do have good drainage. There’s good spacing for each of these trees. It looks like they're planted about eight feet apart or so. And they're kept trimmed so that none of these trees are over more than seven feet tall, and about seven feet wide. So there's room to walk between each of these trees. It really is a very pretty row of citrus trees. The layer of mulch beneath the trees is an excellent idea that helps preserve soil moisture, and it feeds the soil, too, as it breaks down. And I really like your watering system here on your citrus trees. You're using micro sprayers, and it looks like you have three or four surrounding each tree, and the the sprayers themselves are positioned about halfway between the trunk and the outer canopy of the citrus trees. Are these 90 degree sprayers that are spraying outwards when they're on?


JaNahn Scalapino  6:18

I believe that they are quarter sprayers. And we have typically three to five around the trees, the larger trees having more, of course.


Farmer Fred  6:28

By the way, if you don't live in the area, and you can't make it out to the Fair Oaks Horticulture Center, I have links in today's show notes on the citrus micronutrient deficiencies and how to combat them. Because yeah, micronutrients and a shortage of those can also play a part in Citrus success. He mentioned using bat guano. And that is an organic fertilizer, but it is also very high in nitrogen. I think it's like 10%, which for a nitrogen fertilizer  is probably more than you would want to feed a citrus tree. You mentioned that you start feeding your citrus trees in March. And I imagine following the label directions of whatever fertilizer you're using. How many times through the season will you fertilize these citrus trees?


JaNahn Scalapino  7:13

The mature trees that are nicely green, they'll be fertilized just the once. The trees that look a little puny or, and any new tree, will get fertilized typically every three months.


Farmer Fred  7:30

I want to stress one point you did make about fertilizing citrus trees with yellow leaves in the dead of winter:  it's not going to do much good, because the soil is too cold. And the microorganisms in the soil can't really help you move that fertilizer into the tree via the root area because the roots are basically resting. So nitrogen is going to disappear from the soil quickly. So you're just wasting fertilizer. Or,  you're going to overfeed the plants. And when they do wake up, you're going to end up with all sorts of weak new leaf growth that could either be susceptible to a late frost or to an invasion from aphids or whiteflies.


JaNahn Scalapino  8:07

That's correct. We typically recommend that people stop fertilizing after the summer, early September at the very latest.


Farmer Fred  8:16

And what time of the year would you be pruning these trees to keep them at seven feet tall and wide?


JaNahn Scalapino  8:21

We are pruning all year round pretty much, if it's not gonna rain in the near future. And when we see pruning to be done, we’ll do it. Citrus are evergreen, as you know, and we try not to prune when they're abundantly blooming and setting their fruit. But once the fruit is pretty well set and we're past June, we'll look for suckers and snap them off and really try our hardest to keep the tree height down.


Farmer Fred  8:50

If you live in a slightly colder climate and you are growing citrus outdoors, a lot of citrus experts will mention to stop fertilizing after August or September or so. Because any weak new growth that's going to be growing in early fall could be susceptible to a freeze in winter or even early spring. So it depends where you live. And in our environment, and the way the environment is going, yeah, you could basically trim year around.


JaNahn Scalapino  9:16

Yes,  we wouldn't fertilize because we don't want that green flush of growth to occur right as the frosts are starting to bite. But the older mature growth, we don't have any qualms about pruning when we need to.


Farmer Fred  9:31

Another point that John made was that when he dug up the tree, the roots didn't look too good. And then he put it in a pot. So we go back to what you said about starting off on the good foot as far as planting a tree and it may have been root bound to begin with. So let's say you buy a citrus tree in a black plastic container. You take it home, you dig a nice wide hole. The hole doesn't have to be deep, just wide. And you pop that tree out of that black plastic pot and you see the roots going round and round and round. Well, don't plant it that way, you have to basically, it's called. scoring the root ball or separating out the roots.


JaNahn Scalapino  10:12

We’ve found that one of those garden claw forks is ideal for digging in and pulling out the roots, so that you can spread them out a little bit in the hole. And that is what I tried to do at home.


Farmer Fred  10:27

Yeah, that's true with just about any plant. But with citrus, if you have basically a root-bound soil ball, and you just stick it in without freeing those roots up first, that could lead to yellowing leaves.


JaNahn Scalapino  10:39

It could, and the tree will never be a healthy specimen.


Farmer Fred  10:43

Now, John, you mentioned that when you dug up the tree, it didn't look too good, you stuck it in a pot. I hope it was a really good sized pot. And that maybe eventually it can go back in the soil. Because to succeed in a container, a citrus tree has to be in a pretty large pot, like at least a half barrel, if not bigger.


JaNahn Scalapino  11:00

That's correct. Many citrus will do well in large pots, and people will even harvest fruit from them. And it has an advantage. In a cold climate, you can bring them into your garage in the winter. But we do recommend that every few years, you remove the tree from the pot, and trim any roots that don't look good, and give them a little fresh potting soil at the base. And then they should be good for another few years.


Farmer Fred  11:29

And if it's in a pot, but  you have bigger pots, I might even transplant the tree to a bigger pot.


JaNahn Scalapino  11:34

Sure you can, the biggest pot that you can find is what citrus tree will love, if you can't put them in the ground. Putting them in the ground is clearly the better way to go. But not everybody can.


Farmer Fred  11:46

Another tip about planting fruit trees and citrus trees in containers is if you want to keep the root system a little bit more compact. One fruit tree expert told me this and it makes a heck of a lot of sense. Don't let the tree get any wider than one and a half times the diameter of whatever container it's in. So for instance, let's say you have a good sized pot, that might be  two feet across. You wouldn't want to go more than 36 inches wide with that tree. So you're constantly pruning it, and that's okay. But by keeping it compact like that, it doesn't produce more roots, so it'll be much happier and with less stress.


JaNahn Scalapino  12:26

That's excellent advice.


Farmer Fred  12:28

Well, there you go. There's  a whole lesson there on growing citrus trees from JaNahn Scalapino,  Master Gardener here in Sacramento County. Thanks for the citrus knowledge.


JaNahn Scalapino  12:37

Oh, you're so very welcome. Thanks for coming out today. And I'd like to invite people to visit the Sacramento Master Gardener website and see our schedule for open gardens and come on out. It's magical out here.


Farmer Fred  12:51

Maybe come out for Harvest Day, the first Saturday in August. Always a good time here at the Fair Oaks Horticulture Center. I'll have links to that too, in the show notes. Thank you, JaNahn.


JaNahn Scalapino  13:00

Oh, you're so welcome. Thank you.




Farmer Fred  13:08

We get a question from Southern California from Fullerton, from Sarah. And she says, “Hi, Fred. I enjoy your podcast. You and Debbie are delightful and hilarious. Any suggestions on keeping cats out of your raised beds? I'm currently using spiked mats that I bought online. It was suggested to me also to try coffee grounds or cocoa shells. What are your thoughts or suggestions?”


Well, Sarah, the fact that you've already purchased and are using those spiked mats makes me wonder if you're having success with them or not. I checked out those plastic spiked mats that you mentioned. And I think their durability might be questionable, based on some of the comments that were mentioned with that product. These mats seem to be comprised of either individual mats that are about a foot wide and six feet long. Or they come in small rolls that are about a foot wide and of a varying length. It's a mesh screen, the mesh of the plastic looks to be about an inch square. And they appear to have plastic spikes that stick up about a half inch, or perhaps an inch, along the length of the mats and the rolls. Interesting that the picture that accompanied the product, it shows a person working with the roll with no gloves on, which I think might be risky, what with all those spikes. Well, you would know better than I would Sarah about that.


And weeds will grow through the mesh. So you're gonna have to get in there and pull the weeds out without impaling your fingers on any of those spikes. Now, maybe those spikes aren't sharp, but I would think you would feel something if you had to put your hand down flat in our hurry to maybe keep your balance or just as a boost to get back up. No, at least use gloves.


All right, the six foot by one foot mats aren't very inexpensive either. They're about $25 each. So if you're trying to protect a big garden it could be quite an investment.


So, I do use something to keep cats out of my raised beds. I've had raised beds for a long time, and they're made out of wood. I like to sit while I'm pulling weeds from them. So I topped all of my raised beds that are made out of wood with a two by six to sit on, along the top frame. And that's a nice place to  put concrete reinforcement sheets. And that I find keeps the cats out.


The concrete reinforcement sheets are six inch mesh, and it does a good job of keeping the cats and the dogs out. They're also called remesh sheets, they're usually sold in four foot by five foot sections. You can find him in the back aisle at Home Depot or Lowe's near the concrete and bricks. They are available in rolls as well. And these things will last a lifetime.


And what I like about the six inch by six inch grids is that it makes planting a heck of a lot easier, you can actually plant at the proper spacing by just following the grids.


Now with the rolls, just like with those plastic rolls, you can customize the length that is a bit tougher cutting the roll you need a good pair of shears, you need a basically a barbed wire cutting tool to get in there to cut that gauge of wire but it can be done. And that's why I like to use the sheets. The sheets will fit in the back of a van. It scratches the van up, but then for me a van is a cargo vehicle.


I've used them for decades, the cats don't like to be going through it. But the trick is, as I mentioned, about the two by six where I like to sit. That's where you need to place those concrete reinforcement sheets. Don't rest them on the soil because then the cats don't have a problem stepping through it. Just suspend it about an inch or two above ground level. And the soil level in a raised bed is usually an inch or so below the level of the raised frame of the bed. And a four by five foot sheet works perfectly in that regard. And you can easily move them if you need to rake leaves or pull weeds or replant.


Now the key  with using those sheets that are four feet by five feet is the width of the entire bed. And that's why we always say when you're building a raised bed, whatever you're using to build that raised bed is to keep the width at four feet or less. If your raised beds have a wooden or block frame, make them four feet or less wide, it's a lot easier to reach the weeds and it'll hold those concrete reinforcement sheets or the remesh sheets quite easily and keep the cats out. It does work!




Farmer Fred  17:45

From the garden e-mailbag, Steve writes in and says, “I listened to all your podcasts and gotten quite a green thumb from your show.” Well thank you, Steve, for that. He has a tomato question. He says, “The local place where I get my usual tomato plants is no longer doing it. It's where I bought all my tomato and vegetable plants for the summer with great results, but no more. Is it too late to order and plant tomato seeds?”

Steve lives in California, and we here have a long growing season. And he asks, “Who would you recommend to order them from online?” Good question.

Where can you get tomato seeds now and is it too late to plant them? Well here in California you can start tomato seeds here all the way through April, really, for planting by mid June. And you'll be fine. You'll have a long growing season.

But let's talk with Master Gardener Dan Vierria, a tomato head if there ever was one. Dan, what are some good mail order tomato seed companies that you like to use?


Dan Vierria  18:44

I like Tomato Growers Supply. I like Totally Tomatoes. And I found Burpee’s are a real reliable seed company for tomatoes that have good yields and have a good strong history of producing.


Farmer Fred  18:58

A few others  around that I like to use are Seeds N Such.  There's TomatoFest. And then the Baker Creek Seed company, which sells heirloom plants and seeds, and they are at rareseeds.com.


Dan Vierria  19:16

You got me going there on one. Yeah, I do like Baker Creek’s seeds, especially for the good producers. I purchased tomato seeds from them several times. Good point, Fred.


Farmer Fred  19:26

And very colorful packaging.


Dan Vierria  19:30

A very good company.


Farmer Fred  19:31

Oh, Dan. While we have you here. One more question for you. In a recent episode of the podcast, we talked about our favorite tomatoes to grow and you have an always expanding list. I'll post a link to it in today's show notes. Right now, off the top of your head, what are some of your favorite tomatoes to grow?


Dan Vierria  19:49

Well for reliability and if you want a lot of tomatoes, I would say Big Beef is a good one. I like that one. I like Early Girl that's pretty much bullet proof. I like Juliet. It is a grape tomato with big yields and good flavor. Oh, Cherokee Purple is one  I plant every year. It is an heirloom. So those are pretty much my staples. Super Fantastic is also a very good tomato.


Farmer Fred  20:16

Thank you for mentioning that one. Because we talked about it on the podcast. Super Fantastic is a tomato variety that West Coast seed company out of British Columbia says is fine for the west coast of British Columbia. Well, most of us don't live on the west coast of British Columbia, which is a very cool, mild climate. But you're having good luck with it here in the hot Valley.


Dan Vierria  20:36

I've had great luck with it. Also, we've grown it several times here at the Fair Oaks Horticulture Center, and it's been a huge producer and very tasty tomato.


Farmer Fred  20:44

Super Fantastic. That's it. Dan Vierria knows his tomatoes. Thanks, Dan.


Dan Vierria  20:49

Thank you, Fred.




Farmer Fred  20:59

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 the link 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. Or you can go to Speakpipe directly, at speakpipe.com/garden basics. You want to call or text us? We have that number posted at Gardenbasics.net. It's 916–292-8964, that’s 916-292-8964. Email? Sure we like e-mail. Send it along with your pictures to Fred at farmerfred.com. Or again, go to gardenbasics.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

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!


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