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Monday, July 29, 2013

Last Class for Container Gardening

Your final project is due tonight for all credit students  

Here are some of the lecture notes:  

Maintenance: what is necessary to keep containers healthy?
“Clean the terra cotta pots each year to prevent passing along fungi, bacteria or viruses. Remove plants and soil from the pots and bake the containers in the oven set at 220 degrees Fahrenheit for an hour or so to kill anything residing on the pots. Allow them to cool slowly to room temperature before moving them. Another option for cleaning terra cotta pots is to soak them in white vinegar Rinse well and let the clay pots sit for a couple of days to dry out before replanting.” I would try the vinegar solution, but baking my containers? NONSENSE!!

Watering and Fertilizing Plants in Pots
Fertilizers are salts – if you overfertilize, salt build up – my regimen, low fertilizer will prevent this from happening most of the time unless there is excess salt in the clay itself...

Plants in containers need frequent watering compared to in-ground gardens due to limited soil volume and because exposed sides lead to greater evaporation.

Water when the top 1 or 2 inches of potting soil feel dry, saturating the potting soil.

If there is some doubt that soil is thoroughly moist -- if plants wilt quickly or if potting soil pulls away from the container's sides -- occasionally soak pots in a sink or bathtub of tepid water to make sure the potting soil is fully saturated. Never soak plants for more than a few hours; also drain excess water from drain trays to avoid drowning plants by driving out all soil oxygen.

Soluble Salt Buildup in Clay Pots
Plants dry out sooner in clay pots than plastic containers, but the permeability of clay pots can be helpful -- especially when removing soluble salts, which can build up in soil to toxic levels. When clay pots "wick away" moisture from the soil they contain, they also absorb soluble salts. These salts sometimes come from water high in carbonates, salts or other minerals. They also come from inorganic fertilizers -- which potted plants generally need, because they are not grown in true soil -- and sometimes also from potting soil mixes derived from animal manure.

Preventing Salt Buildup
1. Use quality clay containers that will not have a high salt content to begin with.
2. Control the amount of fertilizer you apply – especially of inorganic fertlizers (the blue crap for example).
3. Water as I showed you – water when you water and see that water is flushed through the entire container
Following this regimen will prevent most of the salt buildup that folks experience.

Removing Salt Buildup on Clay Pots
Soak salt-stained terra cotta pots -- without potting soil or plants -- for a few hours in vinegar to remove salt deposits. If pots are heavily salt crusted, soak them for 10 or 12 hours then scrub thoroughly with a steel wool cleaning pad or a wire brush.
Most advice on sterilizing your containers is from people with far too much time on their hands – most of the sterlization at the Learning Garden is done with sunlight and air. Containers are usually allowed to breath between plantings – if they are really dirty, we scrub them out, and are left to dry. In 15 years, we've had no soil born insects or pathengens pass from plant to plant in our containers.
Uusally a 10% bleach solution is recommended. If you have clothes you want to ruin, go for it.

We've done renovation.... Questions?
Use a machete to remove plants from a straight sided container – curved containers are more difficult, if you can find an old saw blade and use it, you might find it works.

Less fertilizer will net you fewer insects – high Nitrogen causes a sweet succulent growth that attracts pests like the Vegas Strip attracts pests of a different sort.

Adapt a policy of 'Acceptable Damage” - how much damage will you allow on a given plant – it will vary from species to species.

Do not plant plants that will have an unacceptable level of pest infestation for you, i.e. eugenia

Do not plants plants in areas they will not fare well. Plants placed in conditions that don't favor them will also attract pests.

ANY spray, chemical and especially organic ones, KILL more than your target species. Consider the plight of the honey bee and think HARD before you spray.

If you must spray, I ask you use organic pesticides and spray ONLY at dusk. Honey bees will have returned to the hive and the pesticide will be dry by morning and so will not harm them. Still, your spraying will kill unintended victims – most infestations are spotted by beneficial insects before humans and the eggs of beneficial insects will be among your victims.

Some of the common LA pests
  • aphids – sucking insects in white, black, green and pink. If the infestation is within parameters, consider first off of leaving it be, if too much for you, then either wash off with water, rub off with a gloved hand – spraying with an insecticide – even an organic one, should be the course of last resort
  • cabbage looper – white moth lays eggs hatching out a voracious little green larvae that can devour an entire plant in a few days – hand picking works. Bt is somewhat innocuous. Attacts mostly cabbage family members, but is similar enough to the hornworms that attact tomatoes and other members of that family – even though it's a different species they are for practical reasons treated about the same.
  • Powdery mildew – we've discussed controls in class
  • Slugs and snails – beer traps, hand picking and physical control

Year 'round Interest
A general, non-specific discussion about how to keep your containers interesting through out the year.

Thank you for your participation in this class - you are what makes this work or not - your enthusiasm is contagious and I know you'll have many wonderful containers planted in the years to come! 

Good luck!  


Saturday, July 27, 2013

Map for Today's Field Trip

I have been struggling to get a map up here... Instead of a map, I can give you a LINK to a map.  

Today at 1:30 we are meeting at:  

Pottery Manufacturing and Distributing, 18881 S. Hoover Street, Gardena, CA 90248 Phone: 310.323.7772


Monday, July 22, 2013

CA Natives In Containers

Some of tonight's high points: 

Seen as hard to grow
Cultivated only in the last 100 or so years – many not even for 50
Most plants in our gardens have been under our cultivation for over 500 years

Why Grow Natives At All?

Save water – even in containers, CA natives are more thrifty with water than most ornamentals
Lower maintenance – some attention, but mostly in containers they are fussless
Lower pesticide use – CA native plants haven't yet grown dependent on human care takers and so have good resistance to pests that you don't find in many cultivated plants
Invite wildlife into your garden – native plants are food for hummingbirds and other birds, butterflies, and many other insects – including many beneficial ones prefer CA natives
Supports a local ecology – even your one or two CA native containers can provide some of the destroyed native habitat for a few animal or insect species

Some thoughts on Growing Native species

We are a part of the Mediterranean Climates,
Mediterranean Climate notes: at or near 40ยบ latitude; long very hot summers, short, cool and more or less wet winters, Mediterranean, South Africa, Australia, Chile and us.
While a large number of our plants in cultivation are also Mediterranean in origin, our plants have a much longer and more pronounced dry spell – most drought seasons in Mediterranean climates are much shorter than ours – i.e. Rome has an average of six months of drought while LA has closer to 9 months.

Our soils also are more alkaline than other systems as well as being mostly Nitrogen free.

These complicate our ability to grow CA natives in ANY cultivated form – let alone in containers.

Keys to Success With Natives in Containers

Try to purchase healthy plants and, especially when just starting out, act conservatively following set scripts as best as you can. Try to plant containers with plants selected from one plant community – i.e. all plants from Oak Woodland, or all Chaparral or some other ecosystem – do not mix desert plants with montane plants. Select plants with similar needs and from similar growing conditions. Some of the CA Native plant communities include:
northern or southern Oak woodland
valley grassland
coastal sage scrub
mixed evergreen and redwood forest
Do not try to bring plants from distant ecosystems into our climate – borrow only from nearby ecosystems that might actually work here.

Learn from your local CNPS chapter – there is the Los Angeles/Santa Monica Mountains Chapter and the San Gabriel Mountain Chapter – both have meetings, programs and plant sales as well as members that can provide a neophyte with a great deal of information.

In addition there is the Theodore Payne Foundation with classes and a nursery out in Sun Valley (and on the web) and Rancho Santa Ana Botanical Garden has their Grow Native Nursery on the grounds of the Veteran's Administration in West Los Angeles.

Plant your natives at the proper time of year. Experienced gardeners can get by planting natives almost any time of the year, but most beginners will want to start their gardens in the fall when the plants will be the most vigorous and likely to succeed.

Established Natives need minimal supplemental water in the ground, but plants in containers MUST be watered, not as much it's true, but they MUST be watered enough. Certainly just planted natives MUST be watered often enough to establish. Use your finger – try for a consistently lightly moist soil. Not too wet, not completely dried out.

Fill your container with a lose free draining soil – LGM Cactus mix is preferred by many nurseries because it does contain CA mycorrhizae and is a good fast draining mix. Use no fertilizers with CA Natives – do mulch if at all possible using some sort of CA plant duff to cover the soil if you can. Anything is better than nothing.

With no fertilizer and low water, growth will be slow minimizing pruning needs etc.

If you get into this and decide to go wild collecting: it is illegal on CA public lands to collect wild plants or seed. Collecting plants or seed on private land, while legal, can be fraught difficulties – never collect more than half the seed of a well established stand of natives – much less if it is not a large stand. You may safely collect more seeds from perennials because they will survive to put out seed another year. NEVER collect any more seed than you can use in the very immediate future!

Try to use ethical commercial sources of seed. Larner Seeds, plant societies, or TPF


Sunday, July 21, 2013

California Natives in Containers

Check out Theodore Payne Foundation's publication, this is part of the material presented on the 22nd.

We'll be creating a container full of natives along with rehabbing some other containers.


Tuesday, July 16, 2013

L. G. M. Company‌, Retail Dealers

You can find LGM products at the following retail outlets.  

Batavia Gardens, Orange
Bellefontaine Nursery, Pasadena
Blue Hills Nursery, Whittier
Brita’s Old Town Garden, Seal Beach
Burkard Nursery, Pasadena
Cerritos Nursery, Cerritos
Covina Garden Center, Covina
 C & S Nursery, Los Angeles
Ellwood Nursery, Rolling Hills Estates
F. K. Nursery, W. Los Angeles
George’s Hardware, W. Los Angeles 
H & H Nursery, Lakewood
Hashimoto Nursery, W. Los Angeles
 J. Harold Mitchell Co., San Gabriel
The Jungle, W. Los Angeles
Kettles Nursery, Pasadena
La Crescenta Nursery, Glendale
Lo’s Nursery, El Monte
Lucky Plants, Santa Monica
 M & M Nursery, Orange
Mission Nursery, San Marino
Moneta Nursery, Gardena
Mt. Fuji Garden Center, Upland
Nuccio’s Nursery, Altadena
Parkview Nursery, Riverside
Pasadena Lawnmower, Pasadena
Peters Garden Center, Redondo Beach
Rainbow Garden Nursery, Glendora
Rolling Green Wholesale, Culver City
San Gabriel Nursery, San Gabriel
San Marino Nursery, San Marino
Sego Nursery, North Hollywood
SY Nursery, Cerritos
Tabuchi Nursery, W. Los Angeles
Temple Garden Center, El Monte
Venice Plants, Venice
West Valley Nursery, Tarzana
Yamaguchi Bonsai Nursery, W. Los Angeles

Vegetable Varieties To Grow In Containers

In general, any variety with 'early' in the name or description will be a good choice for containers as these are often smaller sized fruit or roots and therefore plants.

Also in general, herbs are your 'gateway' drug to container gardening. Almost all the herbs you want to grow are easily grown in our climate. Basil, thyme, oregano and all of those are very easy in containers. Basil is a summer annual while cilantro is a winter annual. Most of the other herbs are perennial and will provide you with delicious flavor all year round. Almost all the herbs are in the mint family are very, very easy to grow, almost thriving on neglect. If you are new to veggies, start with herbs. If you are new to container gardening, start with herbs. They are insect and disease free.

Try to plant flowers among your veggies, make them look good! There is no reason to have your veggie containers look like utilitarian gardens when you can have nasturtiums hanging over the rim, or alyssum or lobelia. Add marigolds in summer, calendula in winter or any plant you think will increase color and appearance. The bonus is the flowers will help deter pests and will attract pollinators. It's a twofer!

Artichoke – one of any variety in a 15 gallon container – you won't get more than four or so chokes per year except in perfect conditions. Green Globe, Violetto are two varieties to try.

Asparagus – a perennial is not a good candidate for container culture. Asparagus roots are planted in late Fall early Winter here and will not produce a harvest for two years. In most container culture, it is simply not feasible.

Beans – you can get one meal of beans out of a 6x6” container of bush beans. They have shallow roots, so six inches deep will suffice, but 8-10 would be better. Beans can have a bush or climbing habit. Bush beans are usually more easily managed in a container, but pole beans need a large container (more depth too simply to balance with the weight of the top growth combined with poles). All beans can be planted among other plants in a container as they supply nitrogen. Do not plant with tomatoes. Some bush beans: Royalty Purple Pod (can be planted earliest because, unlike most beans, will germinate and thrive in cold soil), Blue Lake or Kentucky Wonder are the standards; I love Romano beans and for a yellow bean, Roc d'Or. Pole beans: All the above (except Roc d'Or) have a pole habit counterpart, in addition, Scarlet Runner is a wonderful container climber with some of the showiest flowers in the veggie world. Drying beans are not your best choice for container production unless you have some large containers to hold enough plants to make it worth your money.

Beets – only in a container at least 12” deep and more would be better. Don't expect a huge crop – put in a beet seed about two inches equidistant from one another and the container edge and you should do OK. Remember, when thinning beets, the tops are marvelous in salads. For a red beet, Early Blood Red or Detroit Dark Red are both good; for a real taste treat, Golden and Chioggia beets are super. Cylindra, in a deeper container can be planted closer together because their roots are more carrot shaped.

Broccoli – of all the cabbage family plants, broccoli is one of the most productive in containers – and it's pretty too! One plant per 16” of diameter in an 18” container. If you can find Nutribud, it is THE premier broccoli variety for containers, beyond that DeCicco and Calabrese are good second choices.

Brussels Sprouts, Cabbage and Caulifower – much less performing in containers. Brussels Sprouts are long, slow crop, demanding of nutrition and if they don't get it their way, extremely susceptible to aphid infestations which are murder to deal with when harvesting. Early Jersey Wakefield is a good cabbage – any of the smaller 'early' cabbages are good choices – any cabbage that takes longer than 80-90 days is going to be a hassle and somewhat less than ideal. If it's described as 'late,' forget it. Cauliflower is, as Mark Twain once opined, “ just cabbage that went to college,” and has the same hassles in containers. Early Snowball is your best choice if you wish to ignore me.

Carrots – need a helluva root run so the best way to plant carrots is in with another plant needing a deep root run – like tomatoes. The only container carrot to defy that rule is those little ones like Paris Market that are all of two bites long. In with tomatoes, and 18 to 24” minimum depth, you can try any of the ordinary ones like Scarlet Nantes or St. Valery.

Chard – is not grown by the Swiss and didn't originate there, so I'm moving to call it simply 'chard.' This is an easy to grow plant, if given a bit of room (18” minimum) and you'll get a long harvest over the cool season. Most chards will hang on for two years if you're lucky. Five Color Silverbeet (silverbeet is the Australian name for chard) is a delightful mix of five different plant colors, Red Rhubarb, as the name suggests, is a lovely red ribbed variety. They are all good and will all give you a good harvest.

Collards – are acceptable as container plants. Vates and Georgia Southern are fine choices – they need a minimum 18x18” container per plant.

Corn – oh, for show, I guess you could plant one or two, but corn does not really lend itself well to container gardens – you really need a minimum of 20 plants or so to effect a good stand to pollinate – with poor pollination will result in ears that are not well-filled. If you want the show, plant a few Bloody Butcher plants in a 10 or 15 gallon container and fertilize heavily. They will get to 14' tall and people will be wowing all over them.

Cucumbers – another difficult one in a container, but... the little Persian cucumbers are smaller plants and good choices for your container garden. Most of the others, if you can put a large trellis for them, you can grow most of them – leave Lemon Cucumbers out – their plants are just too aggressive! Cucumbers need consistent moisture.

Eggplant – any variety of eggplant does well in containers, the plants are fine in anything more than five gallons, although the smaller varieties will be more productive. Casper and Pingtung Long are really good choices.

Kale – is a good choice for winter containers. One plant per five gallon (about 18”) in a drift of 3 to 5, depending on your kale consumption or tolerance, will be a good supply for one or two folks. Lacinato is the one chefs rave about, but all of them are good choices for us. It really prefers cool temperatures.

Leeks – are a challenge because they take so long – like garlic. You can plant them in with other plants as a companion to repel insects (like garlic) but don't plan on a helluva harvest. Blue Solaise is one of the smaller ones – but it still takes 100 to 120 days.

Lettuce - and all salad greens are some of the best container garden plants going. They are shallow rooted, play well in close quarters and are quickly grown without much fuss. Choose your lettuces according to the season – there are lettuces that are heat tolerant (All Year Round) and lettuces that love cold weather (almost everything else). There are butterhead lettuces (that are way too expensive at the market) and looseleaf lettuces of many different colors. All of them fun and easy. I can't make it through the lettuce selection of many seed catalogs without ordering way too many packages of lettuce seed! All of the salad greens, endive, escarole, and spinach are just as easy and fun.

Melons – a lot like cucumbers only worse, in terms of space. I don't know that one can get a decent harvest of melons of any kind – the vines are long and need to be trellised and need space. Look for any melon that is listed as 'space saving' or 'compact.' And good luck.

Okra – need a large container – a well grown okra plant will get six feet tall and is a gorgeous addition to any garden. You'll need a 10 gallon container for each plant, well-grown, will net you a bunch of pods. Red Burgundy and Clemson Spineless are a little smaller and better for containers.

Onions – for storage are not going to be a good and productive container plant. Grow scallions or Long Red of Florence or Red Torpedo (Tropea) and eat them fresh.

Peas – are a great container plant. Like beans, peas can be climbing or bush. Choose according to your needs. Remember the bush varieties will produce more of a crop all at once while the climbing will produce more peas over a longer period. Some of the varieties we've enjoyed include Amish Snap (climbing), Blue Podded (climbing) is a gorgeous SOUP pea... leave the peas to dry and use them in soup, and Dwarf Gray Sugar (bush) are all ones to try.

Peppers – are a wonderful container plant just like eggplants and they are very ornamental, if you leave the peppers to mature (all green peppers are just unripe peppers that would have changed to a color if they had been allowed to ripen). If you like 'em sweet, Jimmy Nardellos, Marconi and Sweet Chocolate; for the hotheads, Jalapenos, Habaneros and Joe's Long Cayenne are some ideas, but really, any one you want to grow will be happy in an 18”/five gallon or so container.

Radishes – are one of the easiest root crops to grow – give them 18” or so depth and you'll be able to eat fresh radishes in about a month. French Breakfast, Watermelon and all others are easy as you can get in growing a vegetable. If you like radishes.

Squash – needs a big container. Summer squashes, the zucchinis, crooknecks, all the squashes with soft skins that eaten fresh, are large plants, but if you have the space and give them a 10 or 15 gallon container, you'll do fine. They will probably get powdery mildew, so plan on a short season or start another plant every other month as long as the weather is warm. Once the mature plant has mildew, yank it and start over. For summer squash, I like Lebonese (light green) better than the dark ones, but the dark ones are more productive. WINTER squashes are a whole 'nuther critter, being the hard skin squashes (pumpkins are a winter squash) and take a long time. They are probably among the largest plants in the garden, so, you need a lot of space and perhaps a sturdy trellis. Personally? I'd pass.

Tomatoes – like the other members of that family, are container garden stars as long as you stay out of the really big heirlooms. You will have a lot of luck with all of the saladettes (the smaller two to three inch tomatoes) and cherry types. In my book the paste tomatoes – especially the determinate types – are your container gardens top performers. Burbank's Slicer, Rutgers, Siletz, and Taxi (a yellow) are all determinate and will not get over four feet hall. Almost all cherry tomatoes will be larger plants as will most of the saladette types. In the latter camp, Juane Flamme, Shady Lady, Black from Tula, Cherokee Purple and a million others will do just fine.

Watermelon – find small fruited ones and good luck. These can be grown more easily than winter squash, but they still take a lot of room. A trellis is highly recommended. Small Shining Light, Stone Mountain, Petite Yellow and Golden Midget are candidates for your experiment.


'The Cheat Sheet'

These are all generalizations and they apply to The Learning Garden, located in Sunset Zone 24, less than 3 miles from the Pacific Ocean in an alluvial plain that is barely above sea level. Cold air from the surrounding higher elevations drains into our area and we are reliably cooler than much of the surrounding areas.

If you are growing inland from us, your temperatures will fluctuate more than ours. The further from the ocean a person gardens, the temperatures become less moderate and the effects of heat and cold are more pronounced. While we can grow some cool season crops year round (kale and chard for example), this becomes more difficult without the ocean's pronounced influence.

Plant in the ground: lettuce, carrots, beets, parsnips, potatoes, celeriac, radishes, spinach,
Plant in containers: lettuce, cabbage, broccoli, kale, chard, (these last two can be started now, but they would have been better started earlier – their production will be reduced by the coming warmer weather), peas, fava beans, lentils, garbanzo beans
Otherwise: You are looking in seed catalogs and reading books to figure out which tomatoes, peppers, beans and other summer crops you will be planting. You will order too many seeds despite promises to yourself to not do it this year.

Plant in the ground: lettuce (and other salad greens), carrots, beets parsnips, radishes, spinach, purple beans,
Plant in containers: early tomatoes, basil, cucumbers, summer squash
Otherwise: If you haven't over-ordered your seeds for summer yet, get busy. You're not playing by the rules.

Plant in the ground: purple beans, lettuce, radishes, purple beans, beets, radishes, spinach, set out plants of basil, early tomatoes, later in the month, sow early sweet corn,
Plant in containers: tomatoes, basil, peppers, eggplant, cucumbers, melons, all squash,

Plant in the ground: beans of all colors, lettuce, radishes, beets, spinach, set out plants of tomatoes, peppers, eggplants, basil, you can start planting all corn now
Plant in containers: tomatoes, basil, peppers, eggplant, cucumbers, melons & squash, okra,

Plant in the ground: all basil, eggplant, all melons and all squash (including cucumbers, set out plants of same and all tomatoes, eggplants and peppers) green and yellow beans and all the dried beans; corn too, if you have room
Plant in containers: As in April, but it's getting late – peppers, eggplants and basil are still OK to start, but it's getting late, did I say it was getting late?

Plant in the ground: all the above, but it's getting late... you can still get a crop, but it will be cut shorter by any early cool weather; the last of the corn can go in early in the month
Plant in containers: after starting pumpkin seeds, take a nap

Plant in the ground only out of necessity – extreme necessity
Plant in containers: continue napping
Otherwise: You can begin to think about your cool season seeds now. Get out them catalogs and prepare to over-order those!

Plant in the ground: nothing if you can avoid it
Plant in containers: towards the end of the month, in a shaded location, the first of the winter veggies can be started, cabbage, broccoli, kale, chard, fava beans, leeks, shallots, onions...
Otherwise: You DO have your cool season seeds ordered, yes?

Plant in the ground: nothing, until late in the month, start sowing turnips, parsnips, radishes, beets and carrots – keep seeds moist! Peas, lentils and garbanzo beans can be sown...
Plant in containers: Cabbage, broccoli, kale, chard, favas, cauliflower, Brussels sprouts,
Otherwise: Get your garlic bulbs, shallot bulbs and onion sets ordered – don't wait – they sell out!

Plant in the ground: by now you can begin to set out some of your cabbage, broccoli, kale, cauliflower, chard and so on. Continue with seeds as above... you can also direct sow favas if you want. Potatoes can usually be found about now as well as sets or seed bulbs of onions, garlic and shallots and they all should be planted from now until late November.
Plant in containers: More Cruciferae and favas, celery and celeriac,

Plant in the ground: More of September's plants can be sown – you still have time for all of them except onions, this will be the last month to plant peas, lentils, garbanzos, shallots, garlic and fava beans. Their growing season is too long to get the harvest you would want. Although the legumes can be planted if you are willing to take a lesser harvest or are using them as a cover (green manure) crop.
Plant in containers: I'm still sowing cabbages, broccoli and cauliflower, but Brussels sprouts are a longer season item so they're not a part of my efforts until next season's planting begins.

Plant in the ground: Too little light and too many parties make it difficult to find garden time – but if you have some things left over from November, try to get that done.
Plant in containers: Pretty much the same story, if you have time, do more of all that's listed from November.

There are two big shifts in Southern Californian gardening: At the end of September, beginning of October it's all about the winter crops. At the end of February, beginning of March, the focus all shifts to summer and the heat lovers. Seeds get started slightly before then (if you have the right conditions, up to six weeks before then!).


(Sorry this took so long to get up - I had to 'refresh my cache' to post.... Who knew I had so much cache?)

Monday, July 8, 2013

Coir Vs. Peat


waste product
Shipped from India thousands of miles away,
equires lots of fresh water for cleaning
Coir is less acidic, and lasts longer
dispute about which one holds more water is pretty much irrelevant, since both hold so much water that as a soil amendment, both would dramatically boost soil water and nutrient retention.
Coir contains a great deal of lignin, which makes it very slow to decompose

Peat Moss

Peat bogs are valuable wildlife habitat, valuable carbon sinks, valuable water filters, Renewable?

Peat moss may acidify your soil enough that some of the more sensitive plants may need the soil to be neutralized before they can thrive.
Peat bogs are a natural carbon sink that hold more carbon than all of the world's forests
Peat bogs are also habitats, which mining disturbs.
Large bales of peat moss are cheaper
Liming to balance acidity – (MY NOTE: not a concern for LA as our water is alkaline and the acidity of peat might prove more benefical in the long run... )

The Canadian Sphagnum Peat Moss Association's study supporting peat moss as superior:

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