By: Amy Grant
Lime trees and other citrus trees make beautiful aromatic container specimens. Planting limes in pots will also enable you to move the plant around more easily to protect it from weather conditions, but it may also make the tree susceptible to too much or too little lime tree watering. Watering limes can be a bit tricky since the amount of irrigation may affect the roots, in turn affecting the flowering and production of your citrus as well. So the question is, how much water do lime trees need?
You may wonder when to water lime trees. The simple answer as to when watering limes should occur is when they are thirsty. Watering can be gauged to some extent by the size of the lime tree and its container. In other words, when the upper 1 inch (2.5 cm.) of the soil is dry to the touch, the plant is in need of irrigation. Moisture meters are helpful tools that can be purchased at the garden store. They will measure the moisture at the root level, ensuring the proper watering of limes.
When watering limes, irrigate until the water runs from the drainage hole in the bottom of the container. Don’t let the lime tree sit in water, which can lead to root rot, causing the leaves to yellow and die off. To prevent this, make sure you plant the tree in a well-draining soil medium and lift the pot slightly with a bed of stones. Lime trees thrive with infrequent deep watering vs. frequent although very light watering.
While citrus trees may sustain damage to under-watering, it is more often the result of over-watering that does the most damage. Some container materials such as plastic, metal, and ceramic hold more moisture, while those consisting of wood or clay will dry out more quickly.
Another hint as to how much water your lime trees is to lift the pot once it has been thoroughly watered. The weight of the pot when wet (but drained) will give you a clue as to its dryness, hence when to water.
If the weather is hot and dry, the lime tree should be watered more frequently. Conversely, cooler temperatures slow growth, so watering limes should be reduced in frequency during the winter months. Use a slow release fertilizer, such as Osmocote, yearly in the early spring (March) combined with proper irrigation for a healthy lime tree.
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There might be nothing out of the ordinary about a lime… at first glance. However, limes come in a wide variety of shapes and sizes and even colors! From the shocking red rind of the blood lime to the long tubular Australian finger lime oozing caviar looking spheres, lime tree varieties are a whole world unto themselves.
Limes are warm loving citrus trees, but if you live in colder climates don’t despair! There are a few ways that you can get this wonderful fresh fruit into your garden. Growers in regions 3-8 can choose to grow in a container and simply bring the tree in during the colder months. For gardeners wanting a classic lime, try growing the Persian lime tree or key lime tree. For the adventurous chefs, the kaffir lime may be the tree for you.
Lime trees, like any citrus tree, have a few key needs in order to grow well. Make sure that they get enough warmth, not too much water, have well-draining soil, and add fertilizer to their soil a few times of year. With this kind of loving care, they’ll grow sometimes up to 20 feet tall and provide mounds of limes that can be used in the kitchen for all to enjoy!
Lime trees need consistent moisture to grow well. Water the soil deeply once or twice a week, rather than frequent shallow watering. When the soil is dry to about 6 inches, water the lime tree. Do not let the lime tree dry out, since the leaves will wilt and drop. Overwatering symptoms include yellowing and cupping leaves. The drooping leaves do not perk up after watering. In this case, let the soil dry out a while before watering again.
Suckers grow below the graft union on lime trees. These are rootstock shoots and do not grow the desired citrus variety. The new shoots should be cut off the tree with pruners. Snipping the thorns off the branches does not harm the lime tree. This makes handling the tree easier, resulting in fewer scratches while picking fruit. So you don't transfer disease to the tree, make sure to use sterilized pruning tools.
Above: On average my citrus trees spend about seven months inside, going back out in late April. I have learned, sometimes the hard way, how to care for indoor citrus, so that by mid spring they are in excellent health and ready to make a break for the great outdoors.
Citrus hate having wet feet, and overwatering is the most common cause of their poor health. Do water deeply, but only water again when the pot is close to dry. Nancy Lingner, who provides customer support at LemonCitrusTree (her daughter, Crystal Kim, owns the business) recommends that you drench the pot and “drown the soil” allowing the water to run freely from the drainage holes.
To do this, Nancy likes to keep trees on a stand above a substantial plastic saucer that can accommodate one gallon of runoff. Because of space constraints I use shallow pot feet and smaller saucers. If water in the saucers touches the bottom of the pot, I let it remain in the saucer for up to 12 hours (thirsty trees will absorb this water again). But after 12 hours, I suck up excess water with a turkey baster (yes, really).
I also like to use terra cotta pots. If the outside is dark and damp at the base, this is a sign that the soil in the bottom of the pot is too wet (even if the top is dry), which is not good, so I hold off on watering. In terms of touch and feel, the top inch or two of soil will also transition from dark and moist to the touch to lighter and dry. Time to water.
Signs of overwatering: the soil stays moist every day the bottom of a terra cotta pot looks dark, or green, and is damp to the touch water stays standing in the saucer the leaves are drooping, but not dry and crisp the leaves gradually turn yellow all over and drop little bugs like fruit flies hover everywhere – these are fungus gnats and are an indication that the pots are staying moist too long.
You would grow key limes in containers similar to other citrus trees. There are a few things to be more aware of when growing in containers versus in-ground planting. Trees have more room to grow in the ground, however, sometimes there isn’t enough space to allow that, and container gardening can still give you the opportunity to grow some of the fruit you enjoy. Trees planted in containers will not become as large or produce as much fruit as trees planted in the ground. However, if you live further up north you’ll be happy to be able to bring them indoors when it’s cold outside.
Citrus trees have wide, strong root systems that help them gather moisture in hot climates. Keeping this in mind, when you choose a container you should make sure it has a larger diameter to allow your tree to spread its roots at the surface level. Most tree roots are located in the top 6 to 24 inches of soil. A pot that is 28″ or larger in diameter should be used. Drilling additional holes in your pot might be necessary for drainage. If you live in an area that gets cold in the winter, consider how you will move the pot.
When planting your tree in your pot you’ll want to make sure you plant it at the original soil level. This will ensure that the graft union is above the soil line. Fruit trees are typically grafted to a rootstock, about 4″ to 8″ above the rootball.
Potting soil should always be used for pots and containers. Regular soil compacts. Potting soil is different in that it includes material that allows for aeration and drainage. Materials such as perlite, vermiculite, or peat moss should be mixed into your soil.
When choosing a location for your tree, you should select a spot that gets 6-8 hours of sunlight a day. They can tolerate some shade in hotter zones but thrive in full sun. Potted plants do enjoy a daily misting for humidity. Keep in mind that shadows are longer during winter months, so you’ll want to be mindful of how close you keep your trees to the south side of your yard.
You’ll want the top 2-3″ of your soil to completely dry out between watering. This can be anywhere from once a week to every day. Once the soil dries out on top, you should water until you see water escaping the drainage holes at the base of the pot. Citrus roots like moist but not soggy conditions. The watering needs of citrus will be different when they are in containers because roots will dry out more quickly. A moisture meter can help you determine when it is time to water.
Pay attention to the foliage. Wilted leaves that perk up after watering meaning you should be watering more often. If your leaves are starting to yellow or curl it could be a sign that you’re watering too much (though yellowing can also be a nutrient deficiency).
Trees grown in containers need more fertilizer compared to trees that grow in the ground because they’re environment is very self-contained. Although there are many varieties of citrus trees, their needs are about the same: nitrogen, phosphorus, potassium, sulfur, and calcium. Nutrients that are required, but needed in less abundance, include iron, zinc, magnesium, copper, molybdenum, manganese, chlorine and boron.
The amount you apply will depend on the type of fertilizer as well as the size and age of the tree. Citrus grown in containers should be fertilized every other month during the growing season. Organic, liquid seaweed can be sprayed on the foliage on a monthly basis. Liquid seaweed spray contains 60+ trace minerals and also helps the tree to become resistant to disease.
Any branches that start to grow below the graft union should be cut off because they will steal nutrients from the primary trunk of the tree. Dead branches should also be pruned. Citrus can be pruned for size and shape, but it isn’t necessary. The best time to prune is in the spring after the last freeze has passed but before new growth appears.