Peat starts out at a very low pH and is adjusted upward by adding lime, which also supplies Ca and Mg. Coir starts at a pH that is already too high (around 7.0) for container media, leaving no chance for using lime as a Ca/Mg source. So what are you using that ensures your plants are getting the Ca and Mg they need, and how do you address the high pH issue that needs no attention with bark/peat-based soils? How do you know you're getting your coir/CHCs from a reputable packager? and that the solubles level isn't excessively high ..... until your plants are surviving or failing? Seems like an unnecessary risk to me. Lots of things become the rage when people don't understand the product well. It's only after they've been brought into the light that people start to say, "Hey wait a minute". Lots of people simply decided that coir (or CHC's) are a great idea based on the fact that THEY bought into the idea that peat is not renewable and they wanted to feel they made a wise choice in switching. Look at the impossible claims you hear about products like Superthrive, Eleanor's VF-11, Bloom-booster fertilizers ...... A few people repeat something they heard someone else say, and pretty soon it's an urban legend and touted as the best thing since sliced bagels. There are reasons commercial ops don't use significant amounts of coir and CHCs in media - cost, high levels of soluble salts (are common) and a pH too high to deal with w/o acidification of the irrigation water. "Isnt the point of drainage layer so there isnt a saturated layer at the bottom of the pot?" It may be your intent, but wishing it would work that way doesn't change physics - no matter how hard you wish. 'Drainage layers' do not promote drainage unless the particles in the drainage layer are no larger than 2.1x the size of the particles in the soil. If they are larger than that, water 'perches' in the soil above the 'drainage layer'. "If the styrofoam was rock I could understand the water perch idea." Rock or big chunks of foam make no difference. The water reacts the same way. "The op was asking about making containers lighter. Annuals and alot of plants dont need the 20+ gallon size of large containers for root colonizing. Why have a 100 pound pot if you dont have to. What would you suggest?" One of the best ways, from a scientific perspective, would be to upturn another (plastic) container inside of the one you're planting in and put a screen over the drain hole. Second best would be to insert a false bottom with a wick through it. You could also partially fill the container with soda bottles or milk jugs with screw-on caps. You CAN use chunks of foam or peanuts to reduce the amount of soil needed to fill a container, but these layers of material in the bottom of containers do nothing for drainage. Al

I would agree with Rhizo and Calistoga... this is the base of your business, the root of it so to speak, and if you want to build a good reputation for producing and selling a good, healthy product, you ultimately have to spend a little in order to make it all come together as you want it to. I would recommend doing some reading and research before embarking upon your venture. "Container Soils - Water Movement & Retention XVII" is a great place to begin. You can usually find this article on the first page of this forum. Container growing is vastly different than growing in a garden, so you'll want to address the needs of plants specifically grown in containers. Poor soil can make or break you as a nursery. When I buy plants from any source, or am mixing my own mediums, my preference is a fir bark based, gritty, larger particled, fast draining medium that won't hold a perched water table, and won't require re-potting on a yearly basis, which ultimately saves money, labor, and time. Save the organic methods for the garden... go for a more inorganic approach to container growing. You want to control what happens within those containers, including moisture, plant nutrition, light, etc... it's best to have your information firmly in hand before you begin this sort of business, or you'll fail before you ever get going. I run a small niche business selling plants, and before I begun, I made sure I had a business plan, and I made sure I knew what I was doing... from the soil up. You really don't want to flounder around without an understanding of plants or their requirements, from a more scientific angle. Tapla's article will help you get there, I believe. It helped me more than I can say. A green thumb is nothing more than applied knowledge. Happy Growing!

You didn't state your zone location. In my area of western WA with dry summers & wet mild winters drainage is utmost because things rot in our cold wet soils if I don't amend soil for fall/winter crops. We need to add lime yearly due to the heavy rain leaching the soil. You could consult the county extension gardening resources or consult a local independent nursery for more information about the soils in your area. Mixing it up now sounds like a good idea. Mulch plants after planting. Add compost after harvest. Keep putting organic matter back in on top of the soil & the worms will work it in the rest of the way. You won't have to dig through & mix it all up again. The beauty of raised beds is that you only dig once. If you're planting transplants you could just part the layers & plant them. Seeds will need fine soil so they can break through. Chunks make it more difficult for them. I agree about allowing space for mulch to hold the moisture & provide some frost protection if your climate warrants.

Look at this as a wonderful opportunity. Less organic material for you to find and labor to add for your plants. If I wanted a lawn with the plantings I know how I would go about it. Three to eight inches isn't very much, so it could be all done by hand ... if we're not talking about a ginormous amount of space. First I would get out as many garden hoses as I have and use them to sketch out the wanted lawn area. Doing it this way gives you a good idea of how it will look in real life, as opposed to a pretty drawing on paper. You can leave them there and reconsider after you've lived with the plan a few days. Move as needed. Once your ready to begin, gather up the mulch that's in the future lawn area and use it to create berms in the flower bed areas, keeping in mind these will decrease in height quite a bit over the next year. But with luck you will still have enough added height to add drama to the floral scene. IF the flowers are to be viewed from both sides , the height needs to be in the center of the beds, with tallest plants in the middle. I did this a couple times with a picket fence at the front of the house and the extra height of those taller plants on the small berm not only helped give more privacy to the front yard and front windows, but the street view was much more eye catching. Everything just looked so much bigger than expected. I'm not talking about a high berm, just enough. ;) Vary the heights of the raised areas too or the whole thing gets too predictable. If by chance you find old dead, thatch where a lawn used to be, and it doesn't seem suitable to be planting on top of , this too can be used for added flower bed height. Just clear a space, throw all that thatch can be used, then cover with more of the compost material. Regular shrubs and perennials can work their way through that sort of thing just fine over the next year or so it takes to break down. I have routinely planted directly in mushroom compost that comes from big trucks ( the bagged is finer) and never had any problems. But that doesn't mean yours isn't slightly different, plus your different climate. What about watering an area and then checking later to see how well it holds moisture ? Heck, throw a test plant in there while your at it and see what happens to it. Hopefully you will not need to spend $$ on more soil to maintain a moisture level. Better to spend on plants and cool hardscaping! Oh, and the perfect birdbath.:) Now get out your collection of garden books and magazines and have fun looking at all the beautiful designs you admired in the past. You have a wonderful, fertile blank slate to work with. How exciting.