skizot, first of all, there is the law of limiting factors (see Liebig's law) which should determine whether a fertilizer is needed at all. Then there is the ratio of N,P and K in relation to each other. This ratio is the result of field trials and can be different for the same crop grown on different soil types. By far the most 'problematic' is nitrogen; the usual inorganic sources are very soluble and liable to leaching by rainfall or irrigation (inorganic urea will go from a solid product to a gas directly). To counter this, manufacturers are always seeking to extend the availability of nitrogen; this adds to the cost. I am more interested in the 'N sources' as stated on the fertilizer bag. If the bag proclaimes "16-4-8" and it states "Nitrogen source: 16% derived from urea", then that tells me that I can expect a quick green-up and an equally quick "green-down". If I get a strong shower of rain within a day or two, a great deal of the product will be dissolved and carried to places where it does not need to be at all, really. IBDU is a slow-release form of urea; it will cost more; the application rate will be the same as for untreated urea (lb. Nitrogen/1000sq.ft.) but it will give a more long lasting effect and will be better for the environment. I feel that the homeowner is misled on this issue. One manufacturer marketed the same "numbers" to commercial operators and homeowners. The difference was in the Nitrogen source. The all-soluble was much cheaper but would have to be put down more frequently to maintain the turf quality. Guess who this was marketed to.

I think too, we could chase the question in another direction. What if we asked and answered what's in the soda/juice/sweet tea that offers a potential benefit to the plant and is there anything in the leftovers that is potentially limiting?? In the juice & soda, we know there might be natural or artificial flavorings, neither of which are likely to be beneficial. There is water, which we know isn't a plus. We already know that some of the bio-compounds in tea are potentially limiting. So, we're left with the primary consideration, which is the sugar content. Let's clear the way by saying if the drinks are artificially sweetened, it's almost a certainty that it would have a limiting effect, or at best would offer no advantage to the plant. Even if it was needed and could be used by the plant, sugar couldn't be absorbed by the plant in molecular form. The hydrocarbon chain would need to be cleaved. Sugar (CnH2nOn [n is a number from 3-7]) hydrocarbon chains contain carbon, hydrogen, and oxygen, which are never deficient under normal circumstances, so nutritionally it looks like the leftovers are a bust. What does sugar actually DO when it becomes part of the soil solution? It increases the level of TDS (total dissolved solids and EC (electrical conductivity). What this does is make it more difficult for the plant to take up water and the nutrients dissolved in water. The goal of a good nutritional supplementation program should be to keep TDS/EC as low as possible w/o the level of nutrients being so low it causes nutrient deficiencies. From this, we can see that ANYTHING in the soil solution that is not nutritional is going to be limiting. To illustrate why non-nutrients in the soil solution are limiting, lets say that in a plant growing strongly, 800 ppm fertility is perfect when only the nutrients essential to growth are present in the soil solution, and they are there in the same ratio in which plants use them. Anything lower than 800 ppm carries the potential for deficiencies, and anything above 800 ppm makes it more difficult to absorb water & nutrients. Skewing the RATIO of nutrients in the soil solution even when the total ppm remains at 800 is also limiting. Adding sugar or any soluble substance the plant can't use has to be limiting. At 800 ppm with sugar being 100 ppm, there can be nutritional deficiencies even if the nutrient ratio is perfect. At 900 ppm with sugar being 100 ppm the effect is limiting because it makes it unnecessarily difficult for the plant to take up water - the primary cause of spoiled foliage in houseplants. I'm done. ;-) Al

Floodthelast, last year I used an umbrella to shade some seedlings that were planted in June, during very hot dry sunny weather. This is not good weather for planting or transplanting anything, but can be done with careful watering and shading the plants for a few days. Make sure containers are watered well before planting time - this makes it easier to get the seedlings out and separate the roots. (Since I mostly plant those little babies individually, it really helps.) Seedlings can also benefit from a very dilute balanced liquid fertilizer. I'm strictly organic, so use liquid seaweed, about 1 tablespoon of the seaweed concentrate per gallon of watering can. This also feeds the soil micro-organisms. I've tried fish emulsion, but that attracted raccoons who would dig up the soil looking for the "fish". Seaweed doesn't attract critters. Some people use a diluted compost tea and say this works wonders for seedlings. I dug up an FAQ on this by trudi - Here is a link that might be useful: Fertilizing Seedlings and a Simple Explanation of N-P-K

"When should I fertilize my seedlings?" I begin to fertilize my seedlings a few days after I transplant them into the ground. I intially give them a very weak solution of fertilizer.....that's no more than 25% percent strength solution "Why is the fertilizer applied at a weaker rate?" Plant seedlings are baby plants. We don't feed our own newborn babies steak and potatoes, they get milk which is easier for them to digest. A weak fertilizer solution is easy for the seedlings to utilize, it won't burn their delicate roots. "How do I make the solution 25% strength?" That's easy to do. Prepare your favorite liquid plant food at full strength. If it makes a gallon of liquid food pour off a quart (or four measuring cups) of it into a separate and empty gallon container....this is a great way to recycle a cleaned and washed out plastic gallon-sized milk jug. Add another three quarts of water to it and that will make a gallon of 25% strength liquid plant food. Here's the forumula: 1 quart of full strength liquid plant food 3 quarts of water Mix the plant food and water in a clean container. ===================================================== If you prepare a quart of full strength plant food this is the formula: 1 cup of full strength liquid plant food 3 cups of water Mix the plant food and water in a clean container. ==================================================== "How do I apply the fertilizer?" Give your seedlings a drink with the hose or sprinkler, let them get a good soaking. Don't water your seedlings with a gush of water straight from the end of the hose, you might splash them out of the ground, use an attachment that will give an easy flow of water...like a sprinkler or a shower nozzle. After giving them a drink of plain water give each seedling about a tablespoon of the 25% solution. It's okay if you give them more than that because you've splashed with the jug, it's still just a 25% strength solution. "When can I increase the percentage of food I give the seedlings? About every two weeks give them a higher percentage of food...go to a 33% strength the next feeding, 50% strength after that, and then 75% strength, and then they can get full strength from then on. Here are the other formulas. For 33% strength plant food: 1 part full strength plant food 2 parts water ================================ For 50% strength plant food: 1 part full strength plant food 1 part water ================================ For 75% strength plant food: 3 parts full strength plant food 1 part water =============================== +++++++++++++++++++++++++++++++ "What is N-P-K?" N-P-K is the set of three numbers that you see on containers of plant food. =============================== "What do they mean?" Those numbers reflect the percentage of the particular nutrient weight per pound of plant food. =============================== "What do they stand for and what do they do?" "N" stands for Nitrogen. Nitrogen is the first number. Nitrogen promotes plant growth above the ground. With plenty of nitrogen a plant will grow quickly and have rich green foliage. "P" stands for Phosphorus. Phosphorus is the second number. Phosphorus is beneficial for healthy growth. It helps a plant grow strong roots, it helps with flower production, and it helps make plants stronger to resist diseases. "K" stands for Potassium. Potassium is the third number. Potassium is neccesary for growing strong plants. It helps makes them stronger to resist disease, it helps to make them less susceptible to damage from the cold, and it helps protect them from excessive moisture loss during dry spells.