I posted this at Gardenweb a while back but I trust the expertise of this forum and know the two don't always intermingle. Hope you don't mind me reposing here.

Long story short, I'm currently in a small dorm/house in college with 5 trees to tend and only one partially shaded southern window and a college budget to do it with.

My plants used to be outside, which they loved, growing more than four times their original size in a few months. I kept them in a shady area for 2 weeks then re-potted all of my plants into the gritty mix that is so popular at gardenweb (equal parts screened turface, bark, granite, and a touch of gypsum) and brought them to my dorm, which is kept between 67 and 74 degrees fahrenheit depending on my roommate's mood.

I can't put them outside, my rowdy housemates would destroy them, so they're stuck inside until next spring/summer.

Now what?

Will my measly window provide them with enough light, or will I have to use a grow light to keep them from stretching out of shape in search of a sun they can never reach?

Any advice on fertilization? I'm currently using slightly diluted Miracle Grow with a touch of epsom salts every two days or so.

My plants:









My newest plant is a Meiwa Kumquat courtesy of a good friend in LA who knew I wanted to try a kumquat. I just wanted to eat one, but she found this site called "fourwinds" and sent me one.

She's a great gal.



It came with flowers all over (that smelled like PEZ candies and lilys) and now it has cute little baby fruits everywhere. Can I grow them into full-sized fruits indoors?




Please help me not kill her gift.

Thanks in advance for your help! Its been almost a week since I took those picture initially, and the plants still appear to be healthy, but I'd like to do everything I can to keep them that way.

EDIT: in case anyone is curious, my plants are:
1 Meiwa Kumquat
1 Meyer Lemon
1 Mexican Lime
2 Washington Navels

First, welcome to The Citrus Growers Forum, we are excited to have you as a member. The photosynthesis manufacturing by a citrus tree maxes out at 650 PAR, which is only 1/3 of full sunlight. At levels higher than 650 PAR the tree will not (can not) produce higher levels of photosynthates (sugars, the tree's food source) only through longer hours of light, as during the spring and summer months, do citrus produce additional photosynthates, thus all the additional summer growth. Therefore, if you don't care about optimum growth throughout the winter months, but want to keep your trees healthy, your trees will do fine growing in diffused light during the winter. While in diffused light, you can fertilize them once a month. If you wish to keep the trees in the direct sunlight, for extra growth, during the winter (which will be minimum to none in your dorm room situation), you will also HAVE TO KEEP the tree's root system (potting soil) at 64F or above throughout the winter, to avoid Winter Leaf Drop (WLD). Note: even though your room is kept at 67 -74, the container will be at a lower temperature due to evaporation from the surface of the potting mixture. Some castles in Europe store their citrus trees in an almost dark basement throughout the winter, with no difficulty. The very best to you and your trees. - Millet (859-)

Millet:

So, should he place a heating pad under the pots?

And if I understand you, one can place citrus trees in a dark basement for the winter without ill effects? Dark as in no plant lights or heating pads, but temps well above freezing?

Thanks.

If Stephen keeps his trees in the direct sunlight, as through a south facing window, then he should apply a heat source to the container to maintain a root zone temperature of at least 64F, and if any leaf drop is seen then raise the temperature to 70F for a short time. This will eliminate any winter leaf drop (WLD). If the trees are growing in diffused light no extra heat source should be needed. Personally, I have never over wintered any citrus in a dark basement condition, as I have a greenhouse. However, Citrange a prominent member of this forum, who has one of the two best citrus web sites on the Internet ( http://www.homecitrusgrowers.co.uk/ ) has visited various castles in Europe, and has reported that some castles with citrus collections store their citrus tree in dark basements with no difficulty. I have posted such a post by Citrange below for your information. Also members of this forum store citrus trees in mostly dark or low light garages that do not freeze, also with no difficulty. Hope I answered you question. Regards, Millet (857-)
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Citrange's post:
A few years ago, I was visiting France in late February and stayed in an slightly run-down chateau. I was surprised to discover a very gloomy basement - almost a dungeon - containing four enormous pots with mature citrus trees in them.
The owners told me the trees stayed there every year for three months with no attention apart from just a few waterings, there was no light except from one small high-up window, the basement stayed just above freezing on the coldest days, the normal inside temperature was around 40-50F. The trees were brought out in March, showed little leaf drop and immediately started flowering.
Now, many people would say the lack of light should cause leaf drop, but it didn't.
Millets theory fits this perfectly. No root activity, no leaf activity and the plants are virtually in suspended animation.

My kumquat has dropped many of it's immature fruit, but shows no other signs of damage or stress. Is this a sign that it needs more light? More of something else?

This is probably no problem, as fruit drop is quite common. Typical citrus trees go through three distinct periods of fruit drop. First is the drop of about 70 to 80 percent of the flowers during and immediately following bloom. The second drop occurs a couple of weeks later, involving small fruit of pea-size to marble-size. The third drop occurs in late May-June,(could be later for Kumquats) involving larger fruit, almost golf ball in size. A few fruit on all citrus will continue to drop through final harvest, but that is normal and cannot be prevented. A citrus tree (including Kumquats) will only retain the amount of fruit that the tree is capable of bring to full maturity. - Millet (854-)

This eases my worries considerably, thank you. But is there anything I can do to decrease the fruit drop?

Unfortunately, almost all of the sunlight coming through my window is diffused through a tree... and what the tree doesn't block, the overhang does.

I'd really like to have some sort of supplemental lighting system for my trees. Is there anything anyone here can suggest? I've thought about building a rig using CFLs, but the cost would be almost as much as a small HPS or similar system, so I'm open to about anything.

I found the following web site that explains about the various types of lamps and the costs associated with them:
http://www.littlegreenhouse.com/guide3.shtml