I'm trying to understand more about sizing containers.

I get that you are supposed to not plant in too big a pot at first, but gradually increase with multiple repottings.

But, how do I know which pot size to go to next?

For instance, I just got 2 fragaria vescas that are in 4" pots. Do I repot them in 6" or 8"? And if their full grown size is about 9-12 inches wide, how big should the final pot be?

I also have a salvia 'fancy dancer' that came in a 4" pot. I did repot it into a 9" pot already and it's happy. As it will grow to be 18-24"x18-24", what would be the final pot size needed?

I just bought two 22.24x13.04 49 quart barrel pots for $20 each. The other colors of the same pot and size were $60+ and the tags on these pots show those measurements but then have another descriptor showin them as being 1.5 gallon and fitting a plant with a 9-1/2" diameter. I think they messed up the labels and I got a great deal!

But I'm looking at these pots wondering what will fit in them? Will the salvia be a good fit? Or something bigger?

I also have a salvia x jamensis 'sierra san antonio' to pot. It is currently in a 3" pot. What size container next? And at an adult size of 2-3' x 2-4', will it be a good candiate for one of my big barrel pots?

OK. This is what I did:

1 fragaria vesca in the 6" pot
1 fragaria vesca in the 13" hanging pot (that is sitting on a cement pier block)
1 salvia x jamensis in the 10" pot

Except for the giant pots, I am out of pots. Have to start looking to get more. I guess I should get more in the 10-15" size range as I'm sure the fragaria vesca will outgrow the 6" pot.

I also did some reading and everything says to go with a pot about 2" bigger than the root ball. But how do you know how big your root ball is until you unpot the plant? Or do you assume it's the size of the existing pot?

Yes to your last question. However, lots of variables. I'm going to address outdoor plants like your salvias, not indoor tropicals.

The "rules" about pot sizes have evolved in large part because of the prevalence of peat-heavy potting mixes. If you put a small plant in a large pot and saturate the the peaty, moisture-retaining mix, the small plant can't use up all the moisture so the roots sit there in excessively wet soil that doesn't dry out — an invitation to anaerobic conditions that lead to rot.

However, if you use an extremely gritty, fast-draining soil for your xerics and Mediterraneans, you can plant in larger pots because the water will drain enough to leave oxygen around the roots. They will need watering more frequently than if planted in peaty mixes, but it will also be virtually impossible to overwater them and they'll be more likely to survive winter.

I'm not suggesting to use a monster container right away, but I have no problem putting a 4" pot into 10"-13" for the first year. My summer climate is similar to yours.

Thanks that helps. I've been using Kelloggs organic Raised Bed and Potting Mix Premium Outdoor Container Mix. It seems to drain nicely - I water every few days and the soil seems to dry out evenly throughout the pot. And I don't see any sogginess in the soil.

Okay. I was just sharing my technique and experience re pot size. That looks really heavy and I would keep to small pots if you're using it. And cut it 50-50 with pumice or perlite for the Mediterranean plants.

How do you know it's drying out evenly throughout the pot?

I have a moisture gauge and checked my pots in multiple spots when I first started with containers - close to the plant and further out in the pot. The moisture has been pretty consistent throughout the pot. If the outer edges of the pot are in the dry (red) zone, the area closest to the root ball is rarely above the bottom of the yellow zone. And that's within a couple days of being watered. I haven't had any pot be in the green at the root ball and dry further out.

I suspect that with our temps, no soil will retain moisture for long. And the bulk of the plants are in full sun so get the brunt of the drying heat.

I'll get some pumice to mix in as I repot into bigger pots.

With salvias, how big of pots do you find your plants end up in when full grown?

I figure I need to start stocking up on planters but not sure what to be looking for. And I'd like to add more salvias around the concrete patio in containers - salvias seem to be very happy here and are easy maintenance and will offer a variety of colors.

I love salvias, in part because so many like this climate. I'm rebuilding my garden after a couple of years' neglect, so my examples are limited. The largest pots I have them in at the moment are about 14x14" ish and I think they're either stunted or in decline.
Look:
These are two Clary sages (Salvia sclarea var turkestanica 'Piemont', aka Italian clary sage) and basic Salvia sclarea. Both are described as biennials or short lived perennials and are in their third years. This is new spring growth; they'll get bigger


Same plant last year


BUT here is a volunteer from last summer's seed that just popped up in the gravel path. What a massive difference in size! The yardstick is just to give you an idea of scale. Do note where it's from.


My point is that the pot size can affect the plant size. They all do better in the ground. Although here's a Black&Bloom from a few years ago; it got huge. So....ymmv

I love the yardstick!!!

Do you think bigger pots would help the ones that are stunted?

I know my salvias will grow out of their current pots (6" and 10"). And while I'd love to put them in the ground, I'm just out of ground space at this point. So, I want to give them as much chance as possible to succeed in pots.

No idea about the two clarys. Soil could probably use a refresh. If they're actually biennials, they're on borrowed time anyway.
I've had a S. greggii in a 10" pot for two years that's done quite well. Needs up potting this year. Related to your S. x jamensis.

I thought I'd post this link. While it deals with veggie gardening, the citrus and fig tree container sizes helped me better see how the sizing for larger shrubs, etc, will generally run.

https://www.plantercraft.com/b...

I can't imagine a pot big enough for a fig tree. I guess you could trim it often to maintain proportions and keep it from getting too top-heavy. Plants with such large leaves are tricky for that kind of thing.

I figured they likely meant dwarf fig trees only.

I'm mostly looking at shrubs/small trees between 8 and 12 feet. Like a butterfly bush and a barbeque rosemary, etc. The prior owner cemented part of the backyard - making a basketball court for the son - but it's not next to the house, instead it takes up the back section of the yard.

It's so stark out there and there's no way to add greenery outside of planters. So I'd like to add a few larger plants that can handle full sun and heat and soften up that area. Hopefully, it will help cool down the space a bit too.

I think I would have the same desires in that situation. Have you thought about building a raised planter around the perimeter of the concrete? That would make whatever is planted there higher from the start. If not on all sides, maybe the south or west side to cast some shade over the area? It sounds like a great patio, as far as making lemonade out of lemons goes.

Keep in mind that potted plants in full sun, and especially on concrete slabs, are less able to withstand extreme heat than the same plants in the ground. Many so-called "full sun" plants in pots benefit from midday protection and/or afternoon shade. I wonder if you could rig up a tasteful shade structure on that basketball court.

The patio is at the southeast part of the yard with the fence right at it's edge on those two sides. Behind the south fence is a parking lot for some rentals. To the west is a section that used to have a brick structure on it. Part of the ground is cemented - I did put a raised planter there for the blackberry bushes (who are very happy). The rest is ground embedded with bricks and concrete (chunks and foundation from that structure) - I have four small trees (10-15 ft at full growth) planted there to create some shading and naturalize that area.

I thought about building planters along the south and east fences but if the fence was damaged, it would be difficult to repair as the planters would be permanent. I also couldn't protect the plants from the major winter wind and rain storms that come from the southwest right across the patio. Or get them out of the sun during our heat waves.

I do have a gazebo on the patio. The patio is around 30ft (east to west) by 20ft (north to south). The gazebo is 10*15ft. It is on the southeast corner. I have a seating arrangement under it.

Yeah, I discovered the heat issue with potted plants this summer. I lost all my potted plants (except my cliff maids and ice plants) that I potted in spring. I had them all out on the patio in all day sun all summer and it was too much for them. But to be fair, I wasn't paying enough attention to them to give them a good start.

So, I've reworked my potted plant system. I moved my plant stands with small to medium planters on the walkway on the east side of the garage. They will still get plenty of hot sun and the heat, but will be more protected from the afternoon sun while they get established and grow over this fall, winter and early spring. They will also be right in line with the back door so I will see them every time I let the dogs out so they won't be "out of sight out of mind".

Everything will start there. I'll let them grow there where I can keep watch. Since most are coming to me in 3" or 4" nursery pots, I will keep them in this location until they have gotten close to full size. THEN I will move them to the patio. I have two 13 gallon and one 16.5 gallon pots. I also have heavy duty wheeled bases for them. So I will be able to move them around as needed - moving them under the gazebo during winter storms and onto the walkway out of the direct sun during summer heat waves.

This Saturday I am buying the following three plants to hopefully end up in the pots on wheels:

Aztec pearl Mexican orange
Bicolor butterfly bush
Double take peach flowering quince

If this goes well, then I can see about doing more big plants in the future.

If it fails, then I may give up on greening up the patio.