I have a young Dwarf Meyer lemon tree that I intend to keep in a pot on my deck. Is it better to gradually increase the pot size to encourage a compact root ball or to plant straight into a large container that it will spend the rest of its life in?
pots for clientsShoot, sorry JStorage, I'm going to give the opposite advice. It would be nice, however to see the size of the tree as it is now to be sure of the next pot size.
The whole deal about planting a too small plant in relation to a too large pot is this; not only does the pot and soil have to drain when watered there also needs to be a large enough root system to suck up the water or too much water will be allowed time to cause root rot and other maladies.
A plant that is in proportion to its pot will have a shorter period of new root growth before the top growth starts growing to accommodate those roots. Like a mini ecosystem...The top growth needs moisture from the roots, the healthy roots, as well as the chemicals absolutely necessary to do photosynthesis that provides the plant with usable energy that goes to the roots (for growth and storage), to the leaves for more photosynthesis to feed the plant and accommodate the new growth, the roots when they sense they are in equilibrium with the soil and water and air and chemicals/nutrients will send energy into the top growth to include flowers and fruit.
Putting a too small plant into a large amount of soil in a pot (this is vastly different than the large body of the garden out of doors) causes an imbalance. Mainly moisture which regulates the amount of air available in the soil. Just a little bit too wet and those baby roots are vulnerable to rot.
Not to mention that plant will be trying to fill that soil, bound by the pot with roots. First. There will be no top growth until that happens. That little plant has maybe a 50/50 chance to become healthy, miss out on root rot, during its stressed time where roots are trying to grow with little to no top growth that produces the energy/food necessary for larger roots and top growth...vulnerable to disease, insects big time.
Please send a picture of your lemon. Pop it out of the container it is in and take a picture of the root system. How long has it been in this container? What did the nursery say it had been fertilized with before you became its owner?
Plants can easily take transplanting. They are not that fragile, no way! When healthy they deal with transplanting very well. I always 'fruf' up the roots breaking a few before putting the plant in new soil. That encourages new roots (lots to do with new enzymes from breakage) and stops roots from encircling their own root system. Root bound means plants have been in a certain pot too long and the roots have followed the circular or square boundaries of their pot. Those roots will continue to grow in that direction and could possibly choke themselves off even if transplanted into the garden or a larger pot.
When we planted thousands of bucks worth of plants in a new landscape (thousands of times) heck couldn't do it all myself and had to teach my crews what to do. They were to use a knife to cut at least 3 or 4 vertical lines down that root ball. Sometimes they needed to use a shovel and punch through those roots to stop the circling because some plants were very root bound. Sometimes we had to 'butterfly' the root ball to fit the plant into a tight spot. Sometimes we had to amputate half the dang root ball. Not one single time that I remember did a plant die. Trust me, my crews were not caring humans with a soft touch. Shock never was a problem. Shock becomes a problem with change of environment (sun, shade, more wind), poor soil, poor drainage and temperature changes. Not with transplanting. Plants actually seem to enjoy transplanting...well some plants. Plants used to life in pots will thrive after transplanting into a pot 2 or 3 inches larger than what it was used to. Any more then too much soil versus roots will cause shock.
Planting flower pots and hanging baskets are a good example. One hanging 14" basket cost around $200. One big pot with a tree and perennials and annuals would go for $1000 and they'd hire me every year. And I used the clients own pots, not new ones. That was a larger bill. You wouldn't believe the number of plants that go into these pots. Chop chop, stuff stuff, cramming little plants together in LARGE pots but always with one or two or three larger, more mature, huge root systems planted in that large pot to get soil and water and drainage system going.
It is really a no no to plant a too small plant in a pot too large. Fresh potting soil. Make sure you use potting soil. Use Osmocote fertilizer you will need to only add once or twice per year. Absolutely no compost added, no sand, and no gravel below the soil and above the hole. Use pot feet or pieces of tile to get air under the pot, now that really improves drainage! And always leave a good inch or so between the top of the soil and the rim for proper watering. Let the potting soil dry out some before watering again. During the summer...depending on the pot size and the plant it might be every day. Otherwise, it will not should not be everyday. This is how you train the roots to grow to be able to get at moisture at the bottom half of the pot. All plants need this. Otherwise, saturated soil in the garden and especially pots will kill plants. Gravel beneath the soil causes a 'perched water table' actually ruining any drainage.
Please send a couple of pictures.
If the aim is to get the tree to a size where you are going to have more than a couple of lemons, you're going to need to repot it. The larger the final root mass is, the more leaves it can support and the leaves will then produce the sugars that will produce the fruit.
Now the normal advice is to pot up one size at a time, and the reason for this is mainly water. If you repot into a large final container, the root mass is going to be relatively small in relation to the amount of potting mix you use. So, this means that less water will be drawn off by roots, which means more stagnant water left in the mix which then leads to root rot.
But this scenario depends on a potting mix with water retentive properties. If there is no water retention of note eg. with a coarse mix as used for cacti, then it won't matter what size pot you use because the mix can't hold enough water to rot the roots. And citrus likes a freely draining soil.
So the answer depends on the mix you intend to use. Certainly, avoid any mixes with water gels that increase the water retentiveness.
I would recommend going with the large container and not have to worry about repotting. I am always nervous about repotting because the plant does have to deal with the shock and you have to get it right so as not to damage it. Also you have to time it right so the roots are not constrained by the size of the plant.