If your indoor lemon tree has finally made it through the pollination stage, you can expect it to start bearing fruit – even if it seems like your tree is too big for the pot you are growing it in!
*This post contains excerpts from my book, The Complete Mini-Guide to Growing Windowsill Lemon Trees: A Reference Manual for Northern-Zone Gardeners. The book is a comprehensive instruction manual for growing potted lemon trees indoors, and may be purchased on Amazon in ebook or paperback formats for less than the price of a fancy cup of coffee!
When is a Potted Lemon Tree Mature Enough to Bear Fruit?
For the first few years (the exact length of time depends on the cultivar and age of the tree when you purchase it), the tree should probably be left alone to let it pump resources into a strong trunk and limb system. I know it hurts, but try to pinch off the first blossoms that your tree produces.
When I bought my very first lemon tree, it arrived in the mail with a baby lemon already set and growing on the itty-bitty branch. I was a new gardener with absolutely zero experience growing windowsill fruit, and that little baby lemon was incredibly exciting. Thinking it would be an experimental tree that probably wouldn’t survive container-growing in my cold temperatures of zone-four USA, I let the fruit stay so I could say I had at least grown one lemon before the tree died…
…well, the tree survived and I harvested my lemon, but the trunk has always been misshapen from that early weight. I could have had a bigger, nicer tree much faster if I’d been ruthless from the start.
As your tree gets larger and builds the structure and energy needed to support fruit without harming the tree itself, you can stop pinching off all the blossoms and instead selectively thin out the fruit if there is too heavy a load.
You may not need to intervene at all; I have always found that the lemon tree tends to self-monitor its own fruit load, and if I wait a few months it will typically shed the extras.
Thinning Fruit From Indoor Lemon Trees
As the fruit gets closer to harvesting size, you will need to keep a close eye on how the weight of the lemons is affecting the tree’s limbs. Be thoughtful about when and how much fruit you allow the tree to bring to maturity.
If you are hoping for any fruit, what you definitely don’t want to do is start thinning by pinching off blossoms. For pollination reasons, every flower should stay on that tree until they drop naturally, and any thinning should be done to the fruit itself. It’s highly disappointing to pinch half the blossoms off your lemon tree and then find that of the remaining half, only one or two set any lemons!
Wait until the fruit has actually set, giving it a few weeks to make sure it’s actually beginning to grow before you remove your “spares.” It’s not uncommon for the tree to shed many baby lemons in the first weeks after flowering, and you don’t want to thin out until you know it is truly necessary.
If thinning is needed, always wait until after a potted tree has been moved inside for the winter and has completed seasonal acclimation to your windowsill. If I pinch off during the flush of summer, I risk losing the remaining lemons to the normal fruit drop when the container-grown tree is stressed by the change in environment moving from the patio to the windowsill.
My goal is to leave as many “extras” on the tree as possible until the environment is completely stable and all early danger points have passed.
Supporting Fruit-Bearing Lemon Branches
As the fruit matures, supporting new weight may become necessary.
Don’t try to assist the tree by propping up the limbs themselves. The limb’s sagging springiness is a natural shock system that helps it adjust to the incredible weight hanging off the tips. Propping up those branches only adds another pressure point to their system, making it more likely that they will snap.
What you can do to relieve the tension is to buoy up the fruit. The fruit is the weight dragging the limb down, and your goal is relieving some of this burden.
You can rig up a sling system that hangs off of any convenient portion of the upper trunk or established, stable limbs. If the tree has no limbs large enough to trust carrying this weight, you can set up a hammock-style sling for the fruit with stakes braced in the soil of your plant pot.
Ripening and Harvesting Lemons Grown in Containers
Ripening can and will take most of a growing season, so don’t be impatient!
Lemons are actually one of the faster-ripening citrus varieties. Expect potted lemon trees’ fruit to ripen within roughly six months instead of the eighteen months that other citrus varieties can take. Even nine months is considered within the normal ripening window for a lemon.
Once the fruit begins changing color, final ripening happens swiftly. Don’t feel like you have to pick the lemons the minute they have turned a lovely summer-yellow; if you aren’t going to use them right away, they will keep better if you let them stay on the tree.
Of course, this can be taken to an extreme – you won’t get six months of extra storage ability – but if you are in the middle of a busy week when you notice the fruit on your lemon tree looks ripe, don’t panic. You can feel perfectly safe in leaving the fruit on the tree until you have a chance to enjoy some fresh-squeezed, homegrown lemonade.
Storage Length for Home-Grown Lemons
Once you pick lemons from your tree, take care not to bruise or roughly handle the fruit. In good condition, a fresh-picked lemon will store unwashed in the fridge for approximately the same storage time as a store-bought lemon (roughly 3 weeks, so long as they are whole lemons with no nicks in the rind for mold to start sneaking in).
One of the nice things about homegrown lemons is you know exactly what environment it was grown in. No unknown pesticides, no spray fertilizer, and no corporate concoction of chemicals.
This total control means that you don’t have to feel anxious about zesting the lovely golden rind for use in recipes, soaps, and other projects. Your windowsill lemons are about as organic, safe and healthy as you can get.
Do I Need to “Cure” Home-Grown Lemons?
If you hear about “cured” lemons, don’t panic. This is something the majority of windowsill gardeners won’t need to bother putting any effort into.
In commercial production, lemons aren’t actually picked at the golden-yellow stage that we’re familiar with seeing at the grocery store. Commercially, most lemons are picked at a faded light green color (NOT at the deep dark green of a still-maturing fruit).
These just-matured fruits are then allowed to sit through a curing process until the peel has turned yellow; if trying this out at home, you may also notice the peel smoothing and thinning out as a secondary clue to curing readiness.
Internally, this curing process allows the fruit to become juicier and ready for consumption. However, as a small-scale windowsill gardener, you can let that curing process happen right on the tree. No need to pick green!
The benefit of curing for large-scale growers is that it enables the fruit to survive the handling, packaging, and shipping required for commercial sale. Home gardeners typically do not need this benefit, and can skip the process entirely.
More Hands-On Advice for Growing Lemons Indoors
Interested in learning more about growing potted lemon trees indoors? Check out my book The Complete Mini-Guide to Growing Windowsill Lemon Trees: A Reference Manual for Northern-Zone Gardeners (available on Amazon along with its companion book The Complete Mini-Guide to Growing Windowsill Pomegranate Trees!) or read more excerpts here:
This post was originally published in 2023. The post may since been updated to keep information and links current.