hi
Two things I've used though for different purposes was
fiberglass tarps and agricultural plastic. The first for an above ground 5x10 foot water garden which held water for over 25 years . The second for a shallow marsh garden it also worked IF i can keep the neighbors dog out of it lol.
Since yours will be below ground and needn't be waterproof I'd go for the Ag plastic ,available in rolls of almost any size. I would punch a few holes in the low parts to provide a slow drainage since you won't be growing water/bog plants gary.

Have you thought about maybe newspapering and mulching the entire bed area? All my beds are covered in newspaper with 2-3 inches of pine mulch on top. The mulch 'traps' the moisture and prevents it from running off. So it slowly seeps through the newspaper, which in turn, prevents the moisture from evaporating back out. Every time I dig through the stuff to put in a new plant, I find the soil is nice and moist (and darker [more organic]). Which kind of surprises me each time since I'm on Candler sand (excessively fast draining) as well as on a 3% grade. But the combination works. I have my moisture loving plants grouped in the same bed together and ran a drip line from my rain barrel to them. Every morning this area gets about an hour of slow watering to the roots of the plants and they seem to enjoy it. I may even try growing some hibiscus here this spring/summer and see if there's enough moisture retention for them, though I'm suspecting there won't be.

Thanks for the responses Gary and Leekle.

Gary, I'll definitely give the Ag plastic a look.

Leekle, I do plan on adding mulch to that bed. I didn't get around to it these past six months because the entire yard was under renovation. While the mulch will help some, I already know it in itself won't be enough.

A little west of that bed are two oak trees that provide a good bit of shade. I did a bunch of soil prep, some initial gardening in the area, mulched it, and still had to water it almost 3 times a week.

Before (July)

After (September)

Obviously things will get easier as I continue to mulch, compost and amend the soil over the next few years, but even then, I'm not certain I can provide optimal conditions for these tropicals, short of installing a leaky water main, thus the tarp/liner.

I will take the newspaper/heavy mulch under advisement though, so thanks!

Seems like what your trying to do is make a dry environment into a wet 1?

You might try mulching w/ compost & then put your regular mulch over that - 3-4 inches thick. Too, I've found I need to wet the soil thoroughly before mulching or all is for naught. I use the cheap bagged composted cow manure from HD & don't bother mixing it in. What are you doing w/ the fallen leaves from your trees? They make great humus/compost/mulch.

I've used cheapest clay cat litter as a moisture-holding amendment as well - & that I do mix in.

HTH

Carol,

I only started gardening in June and took most of August off, so I haven't been around long enough to start making use of oak leaves. Obviously (I hope) I'm trying to use everything that drops, but I've built and renovated A LOT of territory on this 1/3 acre, so there isn't much natural organic material to use.

My local lawn guys don't collect grass clippings, and I don't produce enough organic left-overs to even meet 1/100th of my need.

Given 5 years, I'd have great beds and few problems, but I'm being crazy and trying to make up for lost time, attempting to accomplish much within one or two growing seasons.

I have considered tossing down a few bags of #8822 Napa floor dry, mixing it with compost manure and some milorganite. it would improve the water retention, but it still wouldn't be enough to provide consistently moist garden beds.

Though I love Pinellas County, I wish it wasn't quite what it is, that is, the most densely populated county south of Manhattan. Too few horse ranches, almost no farmland, and dirt built from ground shell and fill soil.

Compressed Oak leaves might do the job and last a few years. I would try at least a 12" layer, Lots availabe for free right know, I just picked up 12 bags this morning.. Adding humic acid to your soil will also increase moisture retention.

I agree with the oak leaves. We have already collected about 50 bags. Have been doing it for years. We used to haul horse bedding, which is wonderful stuff for gardening. There are lots of horse stables in the area. I have heard that some even deliver for free.

Here is a link that might be useful: Pinellas horse boarding

Thanks for all the tips and suggestions everyone. As tempting as it was to go with a liner, I guess I'll be trying to go a little more natural.

As hard as it is to believe, there aren't a lot of leaves available. Around my neighborhood most of the oak leaves have been cleared out already. What remains is either lying in rain gutters, or waiting to get mowed and left in place. Don't know if it's just good yard/tree maintenance or laziness. Truth is I should have started collecting/rummaging others' trash sooner lol.

I'm taking a page from Al Tapla's book (or old postings, as it were). The ingredients include:

Sphaghum Moss
Napa Floor Dry
Cheap bags of Compost/Manure
Milorganite
Pine Bark Fines
Oak Leaves I've already moved to the bed
& Whatever I can muster from my compost pile

Going to lay them out across the bed, one ingredient at a time, then give everything a really thorough mixing, down to about a foot or so.

It's not perfect (or 100% organically kosher), but should help increase aeration, moisture holding capacity, and basic biological value. With a decent base, latter additions and improvements should help further improve the soil.

I plan on growing a pretty dense wall this year. If my Musas and EEs take off soon, the ground itself should gain some rudimentary shade, and with all my Canna growing out and reaching 5' last season, breezes won't likely take as big a toll re: moisture wicking, thanks to their spread.

Finally, in a week or two, I'll get around to covering the entire thing with a generous helping of mulch.

This post was edited by Foreverlad on Mon, Feb 25, 13 at 20:58

Foreverlad,

If you want oak leaves I can probably get you all you need :-)

Darren

Thanks Darren, don't encourage me lol.

Mike

Just thought I'd post an update. I started the renovation yesterday. I pulled out all the musas, canna, colocasias, and everything non-tropical.

I partitioned the bed into 5 sections (basically, 5 sections of fence, each one 8 feet wide and 8 feet front-to-back. Each section got 1 bag of Napa Floor Dry, 1 bag of Milorganite, 2 bags of Pine Bark Fines, and one condensed bale of peat moss.

Yesterday I spread out each ingredient, one atop another, flattened it out with a rake, spread an entire bag of pink-label Osmocote, then triple dug each plot for even dispersal and distribution.

Today I harvested about 6 garbage cans of leaves from the rain/road gutters of the adjacent houses, and spread those out amongst the beds. Then I pulled everything I had from my compost pile and gave each bed 5 or 6 shovels' worth. The compost isn't much, but it'll be worthwhile if the microbes survive and thrive.

After that, I counted up my back-drop Banana plants (9 musa, 1 ensete maurelii for the shade), and the front row display of Alocasia Portoras and Red Abyssinians (5 in total) and went out to HD and picked up 15 bags of compost/manure, one bag for each hole dug.

Before planting anything, I watered the entire bed extremely thoroughly, even re-digging the bed another time to make sure everything was evenly distributed and moist.... talk about disappointing. After almost 5 total hours of shoveling, I was still pulling up shovels of chalk-dust fine, seemingly waterproof sand.

All the same, I stuck with it, re-turned the soil, and got my Bananas and Alocasias planted today.

If I had to do it all over again (...and had a truck at my disposal..) I would have doubled up all the supplies I'd purchased. Laid out on the ground, floor dry, bark fines, etc. all look like a lot, but they disappear really quick, even if you're only digging six or 8 inches down.

Tomorrow I'll be focusing on about 50 stalks of Canna, 20 Colocasias, and another 30 bags of 40lb compost/manure.

Sometime next week I'll start focusing on the borders, standards, and fillers. The week after, I'll be planning for irrigation and about 40 bags of mulch.

A little more research and I'll know if I wanna go with a soaker line or drip irrigation. Right now, signs are pointing to soaker hoses, putting out 1 gallon per foot per hour.

When all is said and done I'll provide some photos of the finished bed.

Use newspapers, cardboard, wood chips (you don't need fines). Just pile this stuff up, put mulch on top and plant in it. With Florida heat, stuff breaks down fast and you'll have decent beds in less than a year. Ask for paper bags for your groceries and use those.

Jane

Agreeing w/ jane_ny on the piling up method - FWIW, I learned the hard way that there's no need to destroy your back double digging garden beds here in FL - county extension horticulturalist informed me it just brings RK nematodes closer to the surface. Maybe not a prob w/ ornamentals, but it sure made veggie gardening tough.

Thanks for the additional tips and suggestions.

While I was really good about watering the Tropical Bed these last 7 months, truth is, most of the bed was a dead zone, and I've never had an encounter with nematodes.

Each plant that originally went into the bed was given a full bag of compost/manure and lightly mulched. The rest of the bed was dead sand/dirt, providing no moisture penetration and no signs of life within it. With the exception of a few very hardy weeds, nothing was growing outside of the tropical holes.

I was still REALLY new to the whole gardening thing at the time, so I didn't realize how little affect healthy watering would have on the bed.

Prior to moving in, I'd say most of the area hadn't been touched with irrigation in 10 years. Between the unrelenting sunlight and it being at the bottom of a gentle slope, the sun and the runoff simply tore away at anything worthwhile that still remained. Weed/grass wasn't even growing against that fence when I started work on it. There wasn't anything to grab on to, and no chance for water to penetrate more than the first half-inch.

The bed needed a complete makeover. Even my original idea of installing some form of moisture liner wouldn't cut it, as water would never make it down in the first place.

I've nearly finished my planting. I talked to a neighbor of mine who had apparently held off on raking up his backyard. That conversation ended up providing me 12 bags of leaves to add to the bed, which I mixed into the spots I'd yet to plant, and the rest went to temporary soil cover.

By the end of this week I should be in about as good of shape as I can hope to be.

Welcome to Florida! Where most 'conventional' gardening practices go out the window = J

FWIW, even our heavily composted/amended & mulched veggie beds get that same dry hydrophobic soil(more like dust) when left fallow & unwatered over any extended period, then I have to use the hose & a hoe or cultivator to mix the water in - like making giant mudpies - before applying compost, amendments & mulches.

Something else I've learned is to always fill planting holes w/ water (usually mixed w/ seaweed extract) before transplanting anything.

Thanks Carol,

I've been in Florida for..let's see, carry the one...23 years now, but between living with my parents (leaving the gardening up to my mother), and living in areas that required no gardening, I didn't quite appreciate how unique our environment is, until I started researching gardening tips and studying Gardenweb's forums.

It's kind of funny really, any time I read suggestions for a particular plant, say, Colocasias, I amend each tip with "...unless you live in Florida, in which case, avoid full sun and plant in mud."

There are, obviously, exceptions to my addendum, but it never ceases to amaze me that anything grows and flourishes in Tampa Bay, outside of carefully tended to yards.

Thanks for that info on hyrdophobics. I assumed things would dry out, but I wasn't sure how bad it might be. While planting some borders in that bed today, I checked some random locations and everything is holding up for now. Mind you, that's with low temps and a half-strong sun, but as the plants begin to grow in, produce minor shade, get fed through drip irrigation, and get covered by 2-3" of mulch, I think the bed stands a chance...or so I hope.