This soilless cultivation technique has some inherent limitations, especially when it comes to a large, fruit-bearing tree that typically requires well-aerated soils like avocado.
But there is still plenty of merit for growing avocados without soil, either in a commercial or a DIY hydroponic system.
An advantage of avocado is that you don’t need to purchase expensive genetically engineered seeds. A leftover pit is already enough for you to start a small gardening project.
First of all, you will need to coax this hard seed to crack and sprout. While the sprouting process is simple and similar for different cultivars, it could be a long haul and take several weeks.
You have to pay close attention to an essential requirement for optimum sprouting potential: the pit should come from ripe avocado fruits, and it shouldn’t be damaged or spoiled in any way.
- Remove the seed from the avocado and gently rinse it in lukewarm water to get rid of any remaining flesh.
- When there are still stubborn bits of residue sticking to it, soak the seed for 10 or so minutes so the flesh could soften up. Don’t scrub hard and damage the brown covering of the seed.
- Let the seed dry on paper towels for 2 days, then peel away the aril.
Note: Do everything with care, as a spoiled pit will have little chance of sprouting and growing into an avocado tree.
From a seed to an avocado, the easy and fastest way to grow one!
Figure out which end is the bottom and which is the top of your avocado pit. The end going up is where the stem will break and emerge, while the roots will grow from the bottom of the pit.
Some pits may shape like a sphere, whereas others are slightly oblong. But most of the time, the flatter end is the bottom end, and the top is slightly pointier.
The way the avocado seed sits inside the fruit could also give you an essential clue since the top end is near the fruit’s stem end.
- Grab 3 or 4 toothpicks and insert them around the outer edge of the pit to suspend them in the glass of water.
- Push the toothpicks firmly into the seed, far enough to support its weight. Angle them slightly downward with equal distance between them. They have to be perpendicular to the seed when it’s held upright.
Hanging an avocado seed using toothpicks is the most common method. But it’s a little tricky for beginners, who may even damage the seed after many failed attempts.
Gardeners also need to check the seed regularly to ensure the toothpicks are still intact and keep the seed partially submerged.
A small plastic device called an “avocado tree growing kit” or “avocado seed holder.” It’s a floating bowl with a hole in the middle, which is large enough to keep the seed sufficiently wet all the time.
You would have to order one bowl like that for each avocado seed, and the cost could add up quickly. But it’s still an excellent choice for novice gardeners who have never grown avocado from a pit before.
The whole point of the seedling phase is to keep the bottom of the avocado seed moist at all times.
- Hang the seed on top of a small-mouthed jar or a regular drinking glass using the toothpicks as a scaffold. Fill water into this container.
- The toothpicks should rest on the container’s rim, and water should cover about one-quarter of the avocado seed.
- Repeat this step for each seed, ensuring that each has its glass and the bottom end is submerged correctly.
- Place the containers in a bright and warm spot that isn’t prone to direct sunlight.
- The sprouting process could take weeks, and a substantial amount of water could evaporate during the period. Check the containers and replenish the water over time as needed. You will also want to change the water when it becomes cloudy.
- A small root should emerge from the bottom after a few weeks. A shoot should appear at the top of the seed not much later after that point as well. This small shoot is where leaves will form and grow. Maintain the water level to help the roots survive.
- Discard any seeds that don’t crack and sprout within three months. Replace them with fresh seeds in the same containers.
- When the stems reach about 6 inches tall, cut them in half. The purpose is to make the avocado plant branch and bushy.
- When they grow to 6 inches again, transplant them into a proper hydroponic system so you can have more control over growing conditions.
Some popular commercial avocado varieties can be transferred into and grown in a hydroponic system, including Lila, Brazos Belle, Bacon, Mexicola Grande, Lula, and Hass (the most popular cultivar of avocado).
If you intend to grow avocado indoors in the long term, consider dwarf varieties like Little Cado, Reed, Gwen, Lamb Hass, and Wurtz. These dwarf avocado trees usually require only 10 to 15 feet of vertical space.
Deep water culture (DWC) is the most suitable method among popular hydroponic systems for optimal growth.
It doesn’t require costly investment like commercial products and can provide more water for big trees like avocados than wick systems. DWC is also an easy method to pick up, even for those just getting the first taste of hydroponic gardening.
There are many off-the-shelf systems from different manufacturers that can grow a hydroponic avocado tree from seed. Many DIYers have successfully built a deep water culture system from household items, such as a broken shop.
Avocado trees thrive in intense, bright light. They will survive some shade, but for the best results, put your hydroponic avocado in the sunniest spot you have.
Remember that this only applies after the roots and first leaves have emerged from the seed. Keep the seed out of direct sunlight until it sprouts completely.
Regularly clean the reservoir or bucket DWC as well to make sure there is no salt formation.
As a subtropical plant, avocados prefer warm temperatures, ideally for most 68 to 75°F. Some cold-hardy varieties can survive 20°F and colder climates with some leaf damage and slow fruit growth.
Avocado trees grow best at 5-7pH. They are sensitive to and will suffer when the pH level goes beyond 7, compromising zinc and iron uptake.
Using test strips or digital pH meters to detect any problem with the pH for avocado trees. Commercial “pH up” and “pH down” products are the easiest way to control pH levels in a simple deep water culture system.
Digital pH controllers are more expensive, but they offer more accurate and reliable results.
Avocados grow well with fertilizers made for citrus trees. Nitrogen is one of the most critical nutrients for avocados, but too much of it can burn the shallow roots.
Most mature avocado trees need a lot of vertical space, except dwarf varieties. Be prepared to relocate the containers every few months to accommodate the grown branches and leaves.
An avocado pit usually needs from 2 to 6 weeks to sprout. After that, it may take another 10 or 15 years to bear fruit.
Hass Avocados, the most common cultivar, typically grow into a height of 15-20 feet after 3 or 4 years. But some varieties grow much faster, reaching 40 or even 60 feet within the same time.
Growing avocado from a pit (non-grafted), you may have to wait for 10 years, or even 15 years, before the tree begins to bear fruit.
Many cultivars also yield a crop of fruit every other year. This “biennial fruiting” means producing a heavy set of fruit (up to 200 or 300 per tree) one year and a much lighter crop in the successive year.
Frequently Ask Questions (FAQ)
Can you grow avocados in just water?
Growing avocados in just water is not recommended. It would take weeks or even months of careful, light watering to get even one seed to germinate. That high level of care required makes it impractical for most people.
What temperature is too hot for avocado trees?
Avocado trees, like most other fruit trees, need 70°F – 80°F temperatures to grow properly. The ideal temperature for these tropical plants is about 76.5°F.
The plant’s root system will adapt to the surrounding climate (elevation and/or latitude), but the optimal temperature range is 65°- 90° F (18°-32 °C) for avocado trees’ flowers and fruit to mature properly.
The rule of thumb is you should leave it at least 5 degrees cooler than your nighttime temperature.
Commercially, growing avocado hydroponically is less popular than traditional farming, but there are many reasons why gardeners, even beginners, try this soilless method.
It’s always a fun experiment and helps you pick up some vital gardening skills, whether you want to grow avocado completely indoors as a decorative houseplant or nature your hydroponic avocado in an outdoor system.