I thought I'd add to this thread, that for growing citrus indoors, it can help to learn on a cheaper indicator plant. The one I used is a rhizomatous angel wing begonia. If it grows large, and flowers nonstop, then a citrus will grow well. Anyone else find a good indicator for citrus?

Bonsai, me too. I use just about any herb or annual that normally would not grow well under most circumstance, such a petunia and rosemary

Mike, you've gotten rosemary to grow inside? How? I have tried several times, and though I can grow orchids and citrus indoors, I've never managed rosemary or mint in the same conditions. But, they grow like weeds outside in my area!

Bonsai, pretty easy. Just never over water and don't get the leaves wet at all. Keep them in a south facing window with grow lights that stay on at least 12 hours and they grow pretty well. Lavender grows but looks weak by the time I put it out but hangs on. I think they like hot full sun no light can mimck for hours unless you pay through the nose for electricity. NO fertilizer the whole time until they go out.

Good to know! I might give it another try now that I have the grow lights, I've always used a well draining soil and watched watering, but they always fail to thrive and I eventually toss them outside or give them away. I've always wondered if they need the heat and the temperature swings to grow healthy.

Those trees look great! My Meyer lemon is still going strong indoors, I just upgraded its grow light since it was getting too tall for the last one. What type of lights do you use?

For some reason I have the hardest time getting rosemary to germinate, it's really the only thing I have a problem with. I do have one nice seedling sitting in my starter tray right now though, so we'll have to see how that goes. I transplanted chocolate peppermint and apple mint into 3 gallon fabric pots a week or two ago. So far the apple mint is struggling and dropping leaves but the peppermint is doing very well, already putting out lots of new growth. I have those under their own lights.

As for citrus, I love my Meyer so much I'm already thinking about expanding the collection. I'm open to suggestions!

I have two, one is an LED 3 head light bought off of amazon. Natural light. Doesn't heat up at all. The other is an agrobrite hydrofarm. Between the two I much prefer the LED.

As for citrus suggestions, it really depends on what you like. I very much like the fukushu kumquat for the fruit. Very sweet with a hint of sour. The makrut/thai lime is also really good because it grows well and the leaves make an amazing seasoning, especially for chicken.

I definitely prefer an LED light also. I have a 3-arm light for my starter tray and a 4-arm for herbs, but they aren't quite as bright as I'd like. Good for supplemental light though, the mint in the window loves it and the adjustability is useful. For my tree I just got an HTG Supply LED and I love it, very impressive brightness for only 60W: https://www.htgsupply.com/products/htg-4-0-90w-led-grow-light/

Looks like you may get more light through your window than I do so I needed a bit more juice.

So can you (at least attempt to) grow just about any citrus indoors? Anything you would avoid?

Do you prefer grafted or grown from seeds/cuttings? My Meyer is grafted, I've seen some people on here say citrus grown from cuttings works better in containers.

My window definitely gets enough light to grow citrus without the grow lights. Essentially I get indirect light all day, enough that turning the light on is really not worth it. Then, especially in summer, I get between 6 and 7.5 hours of direct sunlight. It definitely helps to have. I bought the grow lights to help in winter, when I only get between 3 and 4 hours of direct light through the window, and on the many gray days we get in spring and fall.

As for varieties, you can pretty much grow anything, the caveat is that fruit needs heat to sweeten. So the sweeter varieties may not taste the greatest grown indoors. You probably could heat them enough to sweeten them, if you were really determined, but the cost in heating and the discomfort of living in that kind of heat may not be worth it. I have both seedlings and grafted, and I've worked with both grown in a greenhouse for a number of years. I haven't worked with cuttings. I would say both do just fine in containers, you just need to watch rootstock suckers on grafted. My, personal, indoor trees are both seed grown and grafted, but the seed grown are still very young. The grafted varieties definitely fruit sooner. I would watch rootstock compatability if you go for grafted, as some locally grafted varieties in non-citrus regions can have an incompatability that will impact growth. A good nursery will watch for compatability, but not all do. I've noticed this is more common when they don't tell you or know the rootstock. There are some good resources on this from a couple universities in the citrus regions.

Good to know about the sweetness, oranges were at the top of my list but that may be more trouble than it's worth. I could get another grow tent... maybe in a year or two haha.

I'll keep an eye out for the rootstock variety and make sure it's compatible if I do get anything grafted. I plan to propogate what I have too, so when the Meyer or any new trees need pruning I'll probably end up planting some cuttings.

IMHO. Lemon Meyer is desirable to inoculate.

{So can you (at least attempt to) grow just about any citrus indoors? Anything you would avoid?}

In my climate, not all citrus can be grown in a room. There are problems - ovaries fall off, irregular fruiting, Meyer's disease.

{Do you prefer grafted or grown from seeds/cuttings? My Meyer is grafted, I've seen some people on here say citrus grown from cuttings works better in containers.}

This topic is for dissertation, there are many options. Sometimes cuttings are better.

Alex, why would your climate have an effect on growing indoors? You create your own environment indoors and with proper lighting and climate control pretty much anything can be grown indoors. You just need to recreate the trees natural environment indoors.

What do you call growing indoors - greenhouse?

IMHO - What you wrote is theory, for professionals.

You are not the only one to write like that. Give a link to a detailed article.

For non-professionals. In my country, this is not always enough.

In sweet citrus fruits, in greenhouses, often irregular fruiting, all ovaries often fall off.

"There are some good resources on this from a couple universities in the citrus regions."

bonsai_citrus_and_indoor_gardening - I ask you to show these links.

The way I see it, there's no "magic" to growing indoors. Plants respond to light, temperature, air, water, and nutrients; if you're having problems you must not be properly controlling all of those variables. It's not as easy as I've seen a lot of articles claim and most people are forced to make compromises, but if you can manage to create the right environment I don't see any reason you couldn't produce at the same level as a commercial greenhouse. Light and feeding are easily controlled, temperature and humidity can be tricky to get right IME.

Re cuttings vs grafted:
"This topic is for dissertation, there are many options. Sometimes cuttings are better."
Fair enough, I did some more research and decided it wasn't very clear-cut but all I could find were random articles with vague and unsupported claims. I'm curious if you know any good sources?

Alex, I believe in proof as well, the reason I didn't provide links is that rootstock compatability is a well researched topic which has been studied at a number of universities in the US. Specifically some in california. I commented on rootstock as there was a greenhouse in my area selling sick trees on rootstocks with known incompatabilities, recently, so it was a note to anyone reading to check compatability. (There were many people who returned to that nursery for help because they didn't know what they were doing wrong as their trees just died. I found out about it when a friend mentioned they could never grow citrus and then showed me the tag.) This isn't known for all varieties, and for some it's definitely a topic that can take more research, but for a lot of the more common varieties it has been studied for a long time. A great resource in this was written in 1986 by W.P. Bitters at UC riverside, and is titled Citrus Rootstocks their characters and reactions. The manuscript is available through UC riverside, and the same university has many good resources for rootstock compatability which includes a chart for the more common varieties and their rootstocks.

As for growing exclusively indoors, there are few resources, hence why I started the thread.

BonsaI, good job and thanks for all the info above))

"Fair enough, I did some more research and decided it wasn't very clear-cut but all I could find were random articles with vague and unsupported claims. I'm curious if you know any good sources?"

alexcm [z6a] Good research is difficult to do in an amateur setting. There are no good sources. I surveyed 20 experienced indoor gardening enthusiasts with above average knowledge. Nineteen said - cuttings or one / second / third stock no difference. Only one gardener knew the difference!

"1986 by W.P. Bitters at UC riverside, and is titled Citrus Rootstocks their characters and reactions"

bonsai_citrus_and_indoor_gardening Thank you. I read this book many years ago. It is good, but it does not answer all my questions. I was counting on you to show something new.

Alex, as I mentioned before. My mention of graft compatibility in this context was nothing more than a warning to look for common graft compatibility issues in citrus grafted outside of citrus growing regions, as it can be a stumbling block for some growing citrus if they don't know and buy a locally grafted tree on an incompatible root-stock. If you would like to know more about grafting, there are likely many more on this forum who could give you far more resources than I can, and it may be worth starting a new discussion for this purpose. Since I am limited on space, my interest in graft compatibility is mostly with regard to what you need to know when you're looking to buy a tree. I don't do my own grafting at the moment, and will further research the topic when I am in a place where I can. At the moment I cannot. This discussion post is mostly with regards to growing trees indoors, and compiling information from other indoor growers on what works/doesn't. As for the seed-grown/cutting/grafted argument, this is something that others may have more input on. My own trees are both seed grown and grafted, but the seed grown are all young, and not yet fruiting age.

Thought I'd pop in and add to this thread.

My fukushu has been doing extremely well with the hot sun we've had recently and has budded out and started to set a ton of fruit. (Photo is one branch).

I've also recently added a passion fruit to my collection, and it has bloomed. We'll see if it sets fruit in the next few weeks.

I've recently started giving my trees some occasional kelp meal for micros and it appears to have helped the weaker ones. My Nagami has yet to produce any blooms this year, but it is growing a lot of new branches. It requires the most water of my trees and tends to go dry very quickly, especially on hot days.

Not citrus, but an answer to a question I had a number of months ago, can I grow other kinds of fruit? The answer is yes. This is a Nancy Garrison Passion Fruit growing indoors in a pot right next to my citrus.

I've grown tomatoes indoors over the winter in a tent with a 600 watt HPS bulb. The setup was originally for growing pot but as I smoke less I don't have it going 24/7 anymore so I've gone the fresh tomatoes route over winter.

Ken, how are the indoor grown tomatoes? I've always been curious if they're as good as the ones grown outside in summer, or if they're a little more bland. Steve, I've seen your setups, it's really cool what you've managed to do. It definitely seems like a great way to grow rootstock fast for grafting.

I agree poncirusguy's white bucket is a good method for rootstock for cuttings.

I was wondering if anyone has had pest issues growing tomatoes in winter like that ?
Like the bucket idea. Going to put my fig trees in those white ones next year

Indoor grown tomatoes are just as good as outdoor. You just have to thin the herd a bit more. If you let every tomato grow they turn into cherries. Pests aren't a problem as I start the seeds indoors so they never get the chance for pests.

I posted found pictures here and they dissipated into thin air.

Steve, I've noticed that as well. I recently got a notification of a new comment on this thread, but it never showed. Not sure if there's something going on.

Ken, that's good to know. When I eventually have a bigger place I want to try to grow a few varieties indoors, see if I can keep them year round.

Mike, as for pests I've found that most plants grown exclusively indoors don't seem to have many. Pests are really confined to the ones you bring in. The only ones I find that can be problematic are fungus gnats, but those are usually brought in by a bag of soil that has them (best way to avoid this is to just mix mosquito bits into new soil when doing any potting/repotting. The BTI will just kill the eggs and they'll never show up.) or they fly in through the doors in August/September and you just have to make sure to sprinkle mosquito bits on the soil occasionally to make sure that they don't come in and lay eggs on watering day. I would imagine other flying pests in some areas might be a problem as well. Also, I quarantine all new plants to my indoor growing environment for 40 days by themselves so I can look for pests and then treat any and all pest problems before introducing them to the rest of my plants.

Have grown oranges exclusively indoors. Oranges take 7-15 months from bloom to harvest to ripen. It was an incredible amount of work. After that I started growing indoors and moving plants outside in the spring. Than built a greenhouse in the garage that used 100% artificial light to overwinter. This winter my pet project is a Gorilla grow tent.

Growing indoors you have to pay a lot of attention to the VPD. The further North you live the harder it is to control the vapor-pressure deficit.

Over-watering citrus is a bug-a-boo issue for people who use plastic pots. I water my citrus every day or every other day with a garden house outdoors depending on rain and zero issues. I use a potting mix which is sphagnum peat moss based with organic content. Clay pots drain really well outdoors. Indoors the VPD is so low with heating or air conditioning that the VPD sucks the moisture from the clay making it near impossible to over-water. In the winter I water every day indoors. With a good clay pot the water should take care of itself. The only caveat with watering is when someone gets carried away with fertilizer or just has a build up of fertilizer in their potted plants than all bets are off.

Biggest issue I have had growing indoors or in a greenhouse has far and away been insects, over-fertilizing, followed by not having enough light or lights or sunlight burning the plants. Once brought inside insects are near impossible to get rid of until the next spring when the plants go back outdoors.

My lights are Spectrum King LowPro Flower and Spectrum King SK 400+.

Never heard of VPD before, is that similar to humidity in the air?

VPD is vapor pressure deficit, basically it is the difference between how much moisture the air can hold and how much moisture is in the air. In cold weather the air can't hold as much moisture and so your air can be dryer depending on outdoor temp. Usually you would then humidify your air indoors so as to avoid the air getting too dry. It can be more of a problem in some places than in others.

VPD is the measurement of pressure in the atmosphere, which is measured and altered by temperature and humidity. The VPD in a grow room will determine how your plants transpire. This directly relates to your plants ability to consume nutrients and water.

If your VPD is too high or low, your plants will be over or under transpiring, leading to massive problems.

While vapor pressure deficit sounds scientific and confusing, it’s just a metric serious growers use to describe the combined pressure of air temperature, leaf temperature, and relative humidity.

Sun from a window, or grow light can easily raise leaf temperature (20F) putting the VPD in high stress levels which causes WLD. I found spring and fall easy times to grow indoors and winter and summer much harder because of the whole home heating and cooling systems.

That just my personal situation. Other people have different home construction and different climates and will have different experiences.

Hoping this isn’t something beginners have to worry about right now :)

I had gone away for a week and left the air off. I was worried because that week ended up being very hot but when I came back, the plants were thriving with lots of new growth. So I know they don’t love the AC but it can’t be helped. I’m really not looking forward to my first winter with citrus.

The AC isn't so much the problem, (I have both heating and AC in my house, in fact my sageretia theezans lives right under a vent and really doesn't mind it.) The problem is more that when you run heat or AC directly above a plant it can cause convection around the leaves and dry them out. One way to avoid this is to make sure that your plants aren't under any vents or that you close the vent near the plant. I'm lucky in that my growing area is downstairs which only has two vents for a large area, as a result neither the heating nor the AC are extremely effective. So long as your trees are adapted to their environment, you'll be fine. Just make sure they all sit above humidity trays.

Hi Annie, keep the room as cool as possible in the winter. The cooler the room the lower the VPD the less stress on the plant.

Should we give less light as well in the winter if we're using grow lights? I know we should water less.

Just want to thank Bonsai for starting this thread, the forum is lucky to have you! You've been a tremendous help to me and patiently answered all my many questions.

Hi Annie,

https://www.fourwindsgrowers.com/blogs/four-winds-growing/overwintering-your-citrus-trees

https://www.gardena.com/int/garden-life/garden-magazine/everything-you-have-always-wanted-to-know-about-citrus-trees-and-overwintering-them/

The answer to your question depends on whether you choose the Gardena a,b,or c strategy. It is completely dependent on your grow room and what the variables are.

In a home the roots will always gravitate to the temperature of the room. The leaves will be the temperature of the radiant heat from sun+grow light+air. When there is a difference of 20F or more between the roots and the leaves you will have WLD.

Water requirements are on a sliding scale depending on how much transpiration and photosynthesis are taking place.

Annie, well my hope is to compile some good information for indoor growers. I know there's a lot of info out there for indoor/outdoor but not much good info for strictly indoors. I've even been told by many that it can't be done. My trees sort of prove that wrong. Since I've learned a lot, I just try to help where I can.

As for reducing light, it really depends on your grow lights and how cold your room is. If your room hovers below 60, then you can probably do without the lights, if it's above 60, then you want to keep the lights on at least part of the day. I have an LED and a CFL and I've found that at least for my growing environment it can be helpful to extend my day a bit. But your situation may be different.

Heating pads are great for keeping the roots happy when ambient temps drop into the low 60's / upper 50's. Also check out brew belts from the home brewing industry. They work great and are low wattage. Then you can keep your lights on in the winter for better production without leaf drop.

Thought I'd drop in and share for those that are interested (ignore the yellow color, for some reason everything looks yellow and translucent on the camera under this guy's grow light), here is one of the clusters of fruit on my fukushu. It is also budding out again.

Also, and I'll drop in and share a photo when it's done dropping the leaves for this year, but I've noticed my edible fig bonsai drops its leaves and goes dormant every year for fall. Not sure if that's the poor heating in that room and the slight chill it gets, or if it's the lighting. Still deciding if that one will live in my growing area this winter or if I'll find somewhere else for it to reside until it starts growing again.