Advice from the Help Desk of the
UC Master Gardener Program of Contra Costa County
Client's Request: What do you think caused my lemons to be too big (Picture 1). The second picture has a normal size Meyer lemon next to my too big Meyer lemon. All the lemons on the tree this year were like this. Last year most of the lemons were normal size except for three. The tree is about 8 to 10 years old. It's always been in the same pot on my deck. I fertilize it about three times a year. I appreciate any advice you can give me.
Response from the MGCC's Help Desk: Thank you for contacting the UC Master Gardener Program Help Desk with your question about your Meyer's lemon. It was a pleasure to talk to you in order to find out a bit more about your dwarf Meyer Lemon that has over-sized lemons with thick rinds and little juice.
After completing some research, reviewing the photograph of your 10 year old potted plant, and learning more about your fertilizing and irrigation routines, we have some information and suggestions to share with you that we hope you will find helpful.
Fruit Left on the Tree Too Long
Lemons may develop thick, puffy skin when left on the tree for too long after they ripen. You can wait to pick until the lemons have turned fully yellow, but to ensure juiciness and thinner skins, pick them while there is a little green still on the fruit.
Environmental Moisture and Watering
Dry weather or infrequent watering may cause your lemons to have a dry pulp. Water stress may prompt the tree to absorb moisture from the fruit's pulp, resulting in lemons with little juice. This reabsorption may also occur if you leave the lemons on the tree too long after they ripen. To prevent water stress, keep the top 5 to 6 inches of the soil moist; for dwarf lemons grown in a container, keep the top 1 to 2 inches of soil moist. Alternatively, excessive moisture in the air from high humidity levels may cause puffy rinds with a coarser texture and duller color, though the amount of juice may not be affected.
It's Time to Repot your Meyer Lemon
It is probably time to repot your Meyer Lemon. Potted lemon trees require repotting every two to three years, or when the roots begin growing out the drainage holes. The best time to repot your tree is in spring during heavy growth so it has time to establish in the new container.
Select a container one size larger than the current container. For example, upgrade from a 5 gallon to a 7-gallon pot or a 7-gallon to a 15-gallon pot.
Fill the new pot one-fourth full with a potting soil similar to the type used in the old container. Water the soil until it's evenly moist and the excess just begins to drain from the bottom.
Insert a trowel or knife between the soil and pot sides to loosen the root ball from the container. Grasp the tree near its base and lift it up while a second person pulls the pot downward.
Thoroughly examine the roots and locate any roots that are completely encircling the root ball. Slice through these roots with a clean knife; otherwise, they may constrict the root ball as they grow and cause the tree to die. Remove any dead root material.
Set the tree in the new pot. Adjust the depth of the soil beneath the root ball so the top of the root system sits 2 inches beneath the pot rim. The top of the roots should be just beneath the soil surface, and crown roots (root collar area) should show above the soil line.
Fill in around the roots with additional soil until the lemon tree is potted at the same depth it was at previously. Water thoroughly so the soil settles around the roots and add more soil, if necessary.
Possibly Over Fertilizing Your Tree
Most mature citrus require regular fertilization with nitrogen. Your fertilizer should have more nitrogen (N) than phosphorous (P) or potassium (K). Use at least a 2-1-1 ratio. Typically, most other nutrients are available in sufficient amounts in the soil. Nitrogen should be applied in January or February just prior to bloom. The second application then can be applied in May and perhaps a third in June. Avoid late-season fertilization as it may affect fruit quality, delay fruit coloring, and make the rind tough. Dwarf plants or trees in containers with restricted root space may require less fertilizer. Be careful not to over-fertilize as this could cause excessive new growth, which makes trees susceptible to other disorders.
Here is a list of citrus care articles that you may find helpful for the continuing health of your tree:
We certainly hope this information is helpful to you. Please do not hesitate to contact us again should you have any other questions about your lemon tree or other horticultural needs.
Help Desk of the Master Gardener Program of Contra Costa County (WHM /SLH)
Note: The UC Master Gardeners Program of Contra Costa's Help Desk is available year-round to answer your gardening questions. Except for a few holidays, we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA 94523. We can also be reached via telephone: (925) 646-6586, email: email@example.com, or on the web at http://ccmg.ucanr.edu/Ask_Us/ MGCC Blogs can be found at http://ccmg.ucanr.edu/HortCoCo/ You can also subscribe to the Blog (http://ucanr.edu/blogs/CCMGBlog/).
Advice for the Home Gardener From the Contra Costa Master Gardeners' Help Desk
Client's Question and Request for Advice:
CCMG Help Desk's Advice:
Thank you for contacting Contra Costa Master Gardeners' Help Desk.
Before you decide how to handle the container, you'll need to decide what you will plant in it. Some plants may benefit by having a deep rooting area, in which case you wouldn't want to use fill material below the potting soil. (If you need some help in determining if your target plants fit that category, you could inquire at the nursery where you buy your plants or check back with us.)
If you're planning to use the containers for annual flowers or other plants that are shallow rooted or for seasonal display, the deeper planting zone is probably unnecessary. In this situation, for reasons I'll explain below, you shouldn't simply put a filler material in the bottom of the container and then put your potting soil directly on top of the filler.
Here's why you shouldn't put the soil mixture directly into the deep container on top of some type of fill material. Many years ago, it was customary to place pebbles or broken pieces of clay pots in the bottom of planting containers below the potting soil. The thought at the time was that those materials would help the containers drain better. But scientific studies have shown that instead of improving drainage, the pebbles or broken-up clay chars in the bottom of a container actually interfere with drainage and can cause the potting soil to stay over-saturated with water.
Also, I've seen suggestions to fill the bottom of deep containers with Styrofoam packing peanuts (or other pieces of broken up Styrofoam) and put your potting soil on top. The problem with placing potting soil directly over such fill material is that the roots of the plants may start growing down into the Styrofoam fill. Because the Styrofoam won't absorb water, the roots in that area will dry out quickly and not supply the plant with water. Also, the Styrofoam area will have no plant nutrients needed by the plant so you don't want to encourage roots to grow into such fill materials.
If you use the “pot inside the pot” method described above, you can fill the lower part of the deep ornamental container with any type of fill material that doesn't interfere with drainage from the container in which you plant your plants. Be sure that both the deep ornamental container and the container in which you plant your plants have drainage holes and that they are not being blocked by the fill material. (If the container holes are so large that fill material or potting soil will fall through the holes, you can cover the drainage holes with landscape fabric or light-weight screen. The fabric or screen will keep the fill materials or soil from falling through the holes but won't interfere with water drainage.
You could use Styrofoam peanuts or broken up pieces of Styrofoam in the bottom of the ornamental container below the inexpensive container in which you have the plants. The plant roots will be contained in the planning container and won't grow into the Styrofoam. If you choose to use that type of fill, first check to be sure that the Styrofoam materials don't start dissolving when you place them in water. Some of the newer types of Styrofoam-like material is constructed so that it starts breaking down in water. You don't want to use that type of material as fill since it will start shrinking as it disintegrates.
Also, be careful not to make the ornamental container top-heavy. If you need more weight to keep the ornamental container stable, you could use pebbles or rocks or other heavy items as the fill material so long as you're careful not to block the drainage holes. You could put some heavy materials in the bottom, then add a Styrofoam layer and then insert your planting container on top.
Hope you find this information to be helpful and that you create a lovely container display.
Contra Costa Master Gardeners Help Desk
Note: The Contra Costa Master Gardener Help Desk is available year-round to answer your gardening questions. Except for a few holidays, we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA 94523. We can also be reached via telephone: (925) 646-6586, email: firstname.lastname@example.org, or on the web at http://ccmg.ucanr.edu/Ask_Us/