Key Lime Tree
Details: Deep Green Fruit, Very fragrant, Produces Authentic Key Limes
Growing Zone: 4 – 11 on the patio move inside before frost, 8 – 11 outdoors
Mature Height: 6 to 12 feet if unpruned
Mature Width: 6 to 8 feet
Sunlight: Full Sun, Partial Sun
Water Requirements: allow to dry out between watering’s.
Does Not Ship To: CA, WA, OR, AZ
Key Lime tree needs sufficient water for new growth, flowers and to produce fruit that have an extremely high, moisture content. When watering citrus at a rate to meet their needs, it is important for the container to be porous. In plastic pots, the top of the soil may appear dry when soil at the bottom of the pot is still wet. The plastic does not allow the roots at the bottom of the pot to retain sufficient oxygen and that often leads to rotting roots. That is why terracotta flower pots work so well, because they are porous and allow the roots to have moisture and oxygen at the same time.
Planting Key Lime Tree:
In the ground:
If you live in a climate where you can plant you Key Lime Tree in the ground outdoors, we suggest you plant your newly purchased Key Lime Tree in a hole that you dig a hole twice as wide as the root system but not deeper. Depending on the quality of your existing soil you may need to add a locally sourced compost or topsoil to the back-fill soil. We do not recommend using straight topsoil or compost as a back-fill soil because more times than not these products will retain entirely to much moisture and will cause the root system to rot. Adding compost or topsoil will help the young feeder roots of Key Lime Tree to spread through the loose, nutrient rich soil, much easier than if you used solely the existing soil which more times than not will be hard and compacted. The most common cause of plant death after transplanting is planting the new plant to deep. That is why we do not recommend planting in a hole any deeper than the soil line of the plant in the pot. A good rule is that you should still be able to see the soil the plant was grown in after back-filling the hole.
If you live in a northern are where you must plant your Key Lime Tree in a container we suggest first that you select the right size pot with adequate drainage holes. A 2-3 year old citrus tree typically wants to grow in about a 12” diameter nursery pot. A large terra cotta pot is ideal because it will allow the roots of the citrus tree to dry out between waterings. This is very importaant for proper growing of citrus trees. Any pot will do however you will need to be sure the pot will drain. We suggest putting a layer of stones or gravel approximately 1 to 1.5 inches thick. This will allow for proper drainage and assure the drainage holes in the pot do not become blocked over time.
Use a soil mix that is lightweight and drains well. If the mix contains a large proportion of dense, absorbent material, such as peat moss or worm castings, amend with 1/4-1/3 volume of pine bark. This is a good time to add Bio-tone starter fertilizer to the soil and mix thoroughly. Water in thoroughly, Once the roots have settled, we prefer using slow release fertilizers such as Citrus-Tone by Espoma applied to the soil surface, rather than using plant stakes. This avoids any risk of burning the roots.
Watering Key Lime Tree:
In the Ground:
After back filling and lightly compacting the 50/50 mix of existing soil and compost give the Key Lime Tree a good deep watering. This is not to be rushed. Most of the water you put on the plant at first will run away from the plant until the soil is soaked. A general rule of thumb is to count to 5 for every one gallon of pot size. For example a one gallon pot would be watered until you count to 5 a three gallon pot would be 15 and so on. Check the plant daily for the first week or so and then every other day there after. Water using the counting method for the first few weeks. Gator Bags are a good investment that will help minimize the watering chore.
Develop a watering schedule so the roots maintain even moisture, but are not waterlogged. Water before leaves show wilting, and when roots have reached about 50% dryness. Elevate pots on stones in the saucer to keep them above standing drainage water. A moisture tester can be an excellent tool to help determine when roots are in need of a drink. Because most commercial moisture testers rely on an electrical conductivity method, however it is possible to get miss-readings due to high salinity or other conditions. An alternative method recently shared by a New England citrus enthusiast simply employs a plain wooden dowel about the diameter of a pencil. Sharpen it with a whittling method (sharp knife) or pencil sharpener. Then insert this into the pot at varying depths, shallow to deeper, determining moisture using your direct senses (feel, smell, etc.).
Consistency is the key with citrus watering. Citrus trees require soil that is moist but never soggy. Watering frequency will vary with soil porosity, tree size, and environmental factors. DO NOT WATER IF THE TOP OF THE SOIL IS DRY WITHOUT CHECKING THE SOIL AT ROOT LEVEL! A simple moisture meter, available at garden supply stores, will read moisture at the root level. This inexpensive tool will allow you to never have to guess about whether or not a plant needs water. See also: the dowel method, above.
A wilted tree that perks up within 24 hours after watering indicates the roots got too dry. Adjust the watering schedule accordingly. A tree with yellow or cupped leaves, or leaves that don’t look perky AFTER watering can indicate excessive watering and soggy roots. Give your tree water less often.
Citrus prefer infrequent, deep watering to frequent, shallow sprinklings. Deeper watering promotes deeper root growth and strengthens your tree. Generally, once or twice a week deep watering works well for container specimens. Be sure to adjust based on weather conditions! In general, it is probably best to water in the morning, but if plants are dry or wilted it is better to water them right away than wait until morning.
Fertilizing Key Lime Tree:
If you are a beginner at growing plants Key Lime Tree is easy to grow however it may be helpful to know that a very small plant which is planted in the ground will take about 1/8 – 1/4 cup of granular fertilizer. A very large tree in the ground will take 2 – 3 lbs spread around the drip line of the branches (not next to the trunk). This is a very loose estimate, so please read the directions on the fertilizer before applying it.
Never fertilize a plant with a chemical fertilizer if the plant looks sick or wilted. If a plant is struggling due to a disease or root problems, the fertilizer will only add stress to it’s life. Try to cure the problem before adding fertilizer.
When looking at most fertilizers, they are described by three numbers on the bag. An example would be 10-10-10 or 12-4-8. The first of these three numbers refers to Nitrogen, which is the primary element necessary for good, balanced growth within the Key Lime Tree. Plants that are deficient in Nitrogen are usually not growing vigorously, and sometimes exhibit pale colored foliage as in the case of trees. Not all Nitrogen deficiencies result in stunted growth. Sometimes, the growth is taller and longer with less than desirable branching when Nitrogen is deficient. The second number in the fertilizer equation is representative of Phosphorus. A deficiency of Phosphorus may affect the energy transfer in the plant, and result in stunted growth as well. Also, plants with insufficient amounts of Phosphorus may have poorer root systems. Potassium is the element represented by the third number on the fertilizer bag. Potassium is the major element required for fruit trees to produce fruit. Plants that are deficient in Potassium, are usually growing more slowly than normal, have fewer flowers and seed, and are more susceptible to disease than plants with adequate levels of Potassium. Although the three elements just mentioned are the major elements necessary for good plant performance, there some minor elements that are just as important in consideration of plant nutrition.
Minor elements that are not included in the three numbers listing on the front of fertilizer bags are very important considerations when choosing your plants fertilizer. Elements such as Magnesium, Sulfur, Calcium, Iron, Manganese, Copper, Zinc, Boron, and Molybdenum play very important roles in providing plants with adequate nutrition. Many times, less expensive fertilizers are sold that contain only the major elements needed, but not the minor elements. Always be sure to look on the fertilizer label on the back of the bag to see exactly what is included in the fertilizer.
When you have selected your fertilizer and are ready to apply it, be sure to rake your mulch back to the drip line of each plant. Apply the fertilizer according to the label directions immediately on top of the soil, and be sure to water the plant thoroughly after the application. You can then rake the mulch back around the base of the Key Lime Tree. Although it is tempting to spend less time by not raking the mulch back during fertilization, the results will be less than desirable, if the fertilizer is applied on top of the mulch.
Proper fertilization of your Key Lime Tree will lead to healthier and more disease resistant plants, as well as provide you with many more enjoyable fruits. Always, read the label on your fertilizer bag, and follow the instructions.
Mulching Key Lime Tree:
We highly recommend that you mulch your Key Lime Tree with either a ground hardwood mulch or a ground cypress mulch depending on your local availability. Any type of mulch will do but cypress or hardwood mulch will be of a higher quality and provide better nutrition overall as they breakdown. Mulching helps to keep weeds away which will compete with your new investment for water and nutrients. A 2 to 3 inch layer of mulch is sufficient but remember to take care not to cover any part of the stem of the plant with mulch. Its better to leave a one inch gap of space between the mulch and the stem or trunk of the plant.
Pruning Key Lime Tree:
Citrus will look fuller with occasional pruning to shape leggy branches, and can be shaped as desired. Pruning is fine any time of year, except in the winter for outdoor trees. Some trees may develop erratic juvenile growth above the graft. If so, prune for shape and balance. Don’t be afraid to completely prune off an erratic branch if it is too irregular or crossing another branch. Other fruitful branches will replace it. Any growth above the graft can eventually bear fruit. Well-pruned trees have higher fruit yields and are less prone to branch breakage.