4-6 lbs of dolomite will generally raise the pH of 1 yard of media by 0.5 - 1.0 point. 16 (fl) oz of dolomite weighs about 1 lb, so we can use ounces interchangeably (fluid vs weight) for lime. Bark/peat soils usually come in at an unlimed pH of 4.0 - 5.0, so we want to raise them about >1.0 point. There are 80 oz in 5 lbs of lime, or 160 tbsp, which will raise the pH of a yard (202 gallons) of soil about 1 point. The big batch is about 35 gallons (4.5 cu ft) or 1/6 of a yard. We need 1/6 of 160 tbsp or 27 tbsp to raise the pH about 1 point. There are 16 tbsp in a cup, so 27 tbsp is 1.7 cups. Since we need to raise the pH more than 1 point, we round the 1.7 cups up 0.3 cups to 2.0 cups. The change comes as a result of realizing that supplying a single cup of lime might not have raised pH high enough. This can ensure that Ca remains reactive and relatively unavailable instead of (in the case of adding more dolomite) residual and exchangeable. Al

Hello Al - thanks again for all of your posts and the fruits of your research. I am growing four heirloom tomato plants in containers using your 5-1-1 mix. Here in Raleigh the closest thing I could find to pine bark fines was a product by Timberline called "Soil Conditioner" which seems to be close to the ideal size. But I wanted to ask you two questions, which I hope you have the time to answer (and patience, if you've already answered them - I looked and could not find your thoughts on these): 1. I used a run of the mill mulch to top off my 5-1-1 mixes in the pots and to my dismay discovered the mulch was full of fungus gnats. I will try Gnatrol to get rid of them, but it brings up my question - what do you use for mulch for the 5-1-1? Maybe pine bark nuggets instead of this buggy shredded hardwood I'm using? (large size might help to avoid insect eggs or other stuff hiding inside?) Or do you not mulch? 2. And secondly, what do you use for day to day pest control? I'm spraying insecticidal soap almost daily to kill the whiteflies/thrips/aphids that I see on the leaves but I wonder if there's anything better I can do instead of using the toxic stuff (Sevin, etc). Thanks!

Just finished watering my plants and thought of several other variables regarding compost use in containers & potting mix drainage. I don't think you should be concerned about how many seasons it takes for your compost to be used up because different plants have different horticultural needs and would require different types and formulas of fertilizers to thrive and be productive. For example, sun-loving tomatoes and roses need rich and fertile soil (but in alkaline and acidic soils respectively) and lots of water but wildflowers in containers generally will die from over fertilization and watering. Therefore, fertilizers and the amount of compost used should be adjusted according to the horticultural needs of a plant. The amount of compost used and its use should be more as a soil amendment, mulch, and not as a reliable fertilizer in containers even if it does slowly convert usable nutrients through the decomposition process. Additionally, compost in containers probably doesn't get entirely "used up" just like the use of soluble fertilizers in containers and hydroponics and thus a good deep watering to flush out unused salts periodically and monthly is highly recommended. Since the maximum nutritional values in crops and fertility of soil in a garden derived from compost use only come several years later (can't recall at the moment the actual number but want to say 5-10 year range) according one comparative study I read, the fertility of potting mix derived from compost use in containers would theoretically also be the same number of years if not longer (due to less buffer and uncontrolled balance of microbes in containers for decomposition) or at best 1/2-3/4 that duration in the other direction if we assume that there is a higher concentration of beneficial microbes in a smaller area in a container to convert the necessary elements and metals into usable nutrients for a plant. In addition, as the fertility of the container potting mix and porosity change with the growing seasons and crops, you'll need to amend your container mix from time to time either by topping compost or new potting mix for long-term plants or remix and repot your short-term crops. There are three other indicators and usable feedback you could use to monitor your use of compost and drainage - the overall health and appearance of the leaves, the rate of plant growth, and the average frequency of watering needed. There is nothing more joyous to see than a totally unblemished and healthy plant to me. Good tasting fruits and fragrant or beautiful blossoms can only follow once the fertilizers are also adjusted as needed based on day length, maturity, and plant needs. Moreover, you could find out the absolute maximum number of days required for your plants and crops to start to wilt on average between watering as a response and during the active growth period. The higher frequency your plants and crops need to be watered or need water replenished, the healthier and more growth is taking place. But as a compromise for plant health and as a technical and enjoyable hobby for an avg gardener and for water conservation and time investment, a two-day lapse between watering and caring during the active season would be doable and a good buffer both for the gardener and for most of his/her plants.

Hi Al and others, I would appreciate advice on saving sick/dying Picea glauca, in pic.1, please. I bought it on post Xmas sale and it was ~50cm tall, looking healthy, with very bushy top. I repotted it without much root cleaning to keep most original soil with fungus, which I read Picea, like other pines, needs. I planted the rootball with old soil into gritty mix, mostly pine bark fines with seramice, with a bit of gravel, see in pic.2 very "gritty" indeed :); trunk is ~1/2" at the bottom). I used a biggish pot to let it grow freely for a year or two. I also cut the top to encourage lower branches growth but it never happened. Water it when the pot feels light, ~ weekly (it is early autumn here in Sydney) by bottom watering in a bucket, then drain well by keeping the pot at ~45 degrees for a while. Use diluted Nitrosol liquid plant food every two weeks. Keep it on sun for 2-3 hrs, then half shade. Despite all my care (or coz of it ? :), the picea never showed any new growth but started developing warning signs for last 2-3 weeks. Those few thin branches started dying. Their stem turns from brown to greyish-green and gets soggy before dying. See in pic 3&4, that branch in front which is dying now, with grey stem. Other branch died a few days ago. Only three normally looking branches are left. But I am afraid they are facing same fate. Anything I can do to rescue my future picea bonsai at all? Thanks and cheers, Sergey