The problem is that you're using a 100 watt incandescent bulb. And it's not putting out nearly enough light for your plants. That is why they appear so "tall." They're actually stretching rather badly for more light because they're not getting nearly enough.
For every square foot of your grow space you are going to need a MINIMUM of 3000 lumens. For far better results you should try to shoot for 5000 lumens per square foot. You can do this by rigging up multiple compact fluorescent bulbs or CFL's as you will see it often posted. CFL's will emit much more light with lower watts usage. CFL's come with color temperature ratings in Kelvins. To promote strong healthy vegging you should get bulbs with a color rating of 6400k - 6500k. These have more blue light spectrum that the plant uses to grow. It should say on the packages somewhere what the color temperature is. If it sas 2700k that's more of an orange wavelength. You want that color to flower. For the stages before flowering though you'll want the 6500k bulbs. The advantages with CFLs is that you can position them close to your plants because of their low heat output. This keeps that light intensity higher. The farther away your light is away from your plants, the lower the light intensity, and the less light they have for the photosynthesis process. I would suggest buying however many 27w CFLs you need to give you the proper amount of lumens per square foot. Just so you know, the CFLs are those spring-like bulbs that are all coiled up.
If you have the money you can also get an HID lighting system. They come in two different types. One is a Metal Halide or MH. These put out more of a blue/white light that would be great for vegging. For flowering you would use a High Pressure Sodium or HPS system. These produce a color temperature of around 3000k and are great for flowering your plants. You can even use it right from the start to veg and flower. I personally wouldn't bother with an MH fixture, but simply use fluorescent lighting and flower under an HPS. Many other growers on this forum do that. I don't know how many square feet your space above your plants is, but try looking at multiple 250w HPS systems or single higher wattage systems up to 1000w. Now these HID lights get hot and you will need a ventilation system to regulate the temperature of your grow room. From the pics it looks like an attic. You need to bring fresh air into the room somehow regardless of the lighting system you use. And if you go with an HID you will definitely need a way to ventilate that hot stale air out of there. Also, because these lights put out so much heat you will need to keep them higher above the plant canopy or your plants will burn. I think something like 15-22 inches above the tops of your plants. You'll have to adjust it as you go until you find the optimal height.
I didn't see all the pictures, but from the ones I did see I noticed there was no fan present. Get a fan blowing air across them to strengthen those stems. You're probably going to need to make braces for all your plants to hold them upright while the fan blows air across them. If it were outside the wind would do this naturally and the plant would adjust as it needed to strengthen its stock. If you look at my grow journal my plant was stretching like yours. After about 2 weeks with the fan on it the stalk became nice and thick.
About the watering, be sure not to over-water your plants. This will hurt them or kill them. I usually water every 4-5 days. Or I would do a simple test with my finger. If you stick your finger into the soil about 1-2 inches down and it's all dry then give it a good water. If it's still wet then give it another couple days before watering again. You don't want the soil to be sludge or the roots won't be able to grow through the soil easily.
I hope this helps somewhat. You have a lot of trees there and you're going to need to get them the proper lighting and ventilation asap for them to grow well. Good luck on your grow.
edit:
Here is a great thread on compact fluorescent lighting by CyberQuest
http://www.marijuanapassion.com/forum/showthread.php?t=8581
. Read up on growing, lighting, soil mixes, nutes, air circulation, humidity, growing then I think you'll see the point.
