Question
hello my name is Korey and I'm in 4th grade. I'm doing a science project on tomatoe plants. My topic is will a tomato plant grow better using cow manure with a mixture of water or miracle grow. I know this is short notice but if you could answer me by thursday it would help me a lot with this part of my paper. I have to research this and I really don't know where to look.Any help would be appreciated, thank you. Also how often should I use these on my tomato plants

Answer
If using cow manure, try to buy aged or composted cow manure. If using fresh cow manure you burn the plants (burning in plant science is when the high salt contents of the cow manure pulls water away from the roots rather than letting it go into the roots, thus starving it from water making it die).

If using cow manure, mix it well into the soil and plant the tomatos in it. Then top dress the plant with cow manure once every 14 days with a handfull of composted cow manure. Topdressing means laying a small amount of cow manure on top of the soil (1/4"). The nutrients in the cow manure will penetrate into the soil and roots with the water.

You can use about 3 handfulls of cowmaure mixed into the existing soil at first. Do this by mixing the handfulls into a 1x1 foot plot and make sure the manure is mixed into the top 10-12" of soil. Then plant your tomato plants into this mix of manure and soil. After this add a thin layer on top of the soil every 3-4 weeks. This should just be a small amount.

If using miracle grow, mix 1 tsp in a gallon of water and water every 14 days. Miracle grow is available in boxes at home depot, lowes, walmart, etc and will have the numbers 15-30-15 printed on the box.

Note: with both products you need to water well at time of fertilizing. You should also water reguarily between fertilizer applications (with clear water).

Here is some science information you may want to think about when writing your report.

Plants need several key essential nutrients to grow. Essential nutrients are nutrients required for plant growth. Without them the plants die. Most nutrients the plants get directly from the soil,air or water but a few nutrients the plants consume (use) in greater quantity than nature can replace naturally, and we therefore fertilize to make the nutrients available.

For most plants in most soils, the 3 key nutrients plants need are NITROGEN-PHOSPHOROUS-POTASSIUM. We get our nutrients (sodium, potassium, a-vitamins etc) in our diet, but plants do not eat. They product their own food through a process called "photosynthesis". Very briefly, this is when plants combine nutrients (call it: raw materials) together with water and carbondioxide (from air) using the sun as an energy source to create the transformation. Therefore, instead of food, plants need the basic elements (which we call nutrients) and they then produce their own food.

Whether you use Miracle Grow or Cow Manure, all you do is to resupply nutrients to the plants. These nutrients the plants use to make their own food. Cow manure contain nutrients in an organic form (as large complex organic molecules). Microbes in the soil break these large molecules into very very small molecules which can then penetrate the cells in the plants and be taken up through the roots with the water. Miracle Grow is a factory made collection of nutrients. It contain plant nutrients which are already broken down into the very small molecules. You can say that Miracle Grow is the engineers way of making the same molecules available to the plants, but without the smell (neat, eh ??)

If you look at the package, the 3 numbers: 15-30-15 means that they contain: 15% Nitrogen (N), 30% phosphorous (P) and 15% potassium (K). This ratio (N-P-K) is very common for fruiting and flowering plants. E.g. plants which produce fruit require relatively high levels of phosphorous and potassium. Compare these ratios to lawn fertilizer which would be 29-3-4 for example (e.g. mainly nitrogen).Therefore, miracle grow is replentishing lots of potassium and phosphrous which the tomato plants are likely to grow.

Cow Manure has numbers 0.3-0.2-0.1 (depends a bit on the kind of manure, and how it is aged, but above numbers are pretty close). Since Cow manure only contain 0.3% nitrogen, 0.2% phosphorous and 0.1% potassium you would need to apply MUCH MORE cow manure than miracle grow fertilizer. e.g. where you may need to add 1 tsp miracle grow, you need to apply 50 tsp cow manure to get the same amount of nitrogen from the two products (15 / 0.3).

This is the reason for using more manure than Miracle grow. If you only added 1 tsp manure you would be applying less than 1/50 of the nutrients required by the plants.

A few logical conclusions:
- see if you can confirm them.

Since the N-P-K ratio of manure is 0.3-0.2-0.1 it means that there is realtively high levels of nitrogen COMPARED to phosphorous and potassium. Generally this means more leafy growth but less fruit and flower production. My guess is that you get plants which are very dark green, heavy foliage, but better fruits with Miracle grow. This is because the manure is relatively high in nitrogen (comparably).

Example Miracle grow has a ratio of 1-2-1 (NPK 15-30-15). The Manure has a ratio of 3-2-1. This means that manure has 3 times as much nitrogen as potassium (K). Miracle grow as equal amounts of nitrogen and potassium (K). Manure has 1.5 times more nitrogen then phosphorous whereas miracle grow has 1.5 times more phosphrous than nitrogen.

Generally tomato plans should be fertilized with fertilizers having ratios of 1-2-1 or 1-2-2 (latter is better). Miracle grow comes closer to this than manure.

Finally, tomatos are very fast growing plants which consume lots of nutrients quickly once the soil is warm. If you apply Miracle grow every 14 days you make nutrients consistently available. Manure takes time to break down in soil (microbes must do this and it takes time). Manure is a lot faster than most organic fertilizers, but there still is a lag time. Therefore very fast growing plants like tomatos are likely to respond more favorably to Miracle grow (if applied regularily) than manure (which must be brown down by microbes).

I hope the above gave you some inspiration.