How to grow avocados indoors: Go-to methods that bear fruit

Oh, the elusive and seductive avocado–who hasn’t seen an avocado pit on toothpicks dangled over a cup of water and wondered, “does that really work?”

The answer is yes! It’s entirely possible to sprout an avocado seed at home, and with dedication and care, to grow an avocado tree that grows up to bear fruit one day. Read on for some comprehensive background on everyone’s favorite savory fruit, and how to grow avocados indoors. 

History of Avocados

The avocado, Persea americana, traces its lineage to south-central Mexico, in the neighborhood of between 7,000 and 5,000 B.C. This, however, was a wild variety that wasn’t cultivated until several millennia later. Ancient avocados have been discovered in Peru, buried with Incan mummies as far back as 750 B.C.(1) That means humans have been loving avocados for close to three thousand years. And who could blame us?

We aren’t entirely certain when cultivation of the avocado began in Mexico, but it could have been as early as 500 B.C. The first time “avocado” crops up in the English language is 1696, but Spanish conquistadores were the first Europeans to stumble upon them in their travels to Mesoamerica. 

Avocados in America

Right around the turn of the 20th century, a handful of nurserymen and farmers began to take an interest in the commercial cultivation of avocados in California. One of those men, F.O. Popeno enlisted a man named Carl Schmidt to explore Mexico City markets for a suitable species of avocado.

Of the 25 species sent to California for cultivation, one stood out above all others: the green-skinned “Fuerte.” The California avocado industry was built on this cultivar until in 1972, it was surpassed by the Hass avocado.(2) This variety had many advantages over the Fuerte, the most notable that a tree could produce fruit in only a few years time and those fruit shipped exceptionally well. This is the avocado that has conquered the world market. 

Every growers dream. Yum! Image: Kim Starr

Varieties of avocados

Because most of us have only experienced one or two avocado varieties at the most, it may come as a shock to learn that there are, in fact, over 50 known varieties.(3) Most of these are far-flung and extremely localized to their native region.

Growing to over 20 feet, most commercially grown varieties of avocados are not suitable for growing indoors long-term. For indoor cultivation there are a number of dwarf varieties with mature heights between 8 and 16 feet. The dwarf varieties of avocados include ‘Gwen,’‘Wurtz,’ ‘Lamb Hass,’‘Holiday,’ ‘Reed,’ and ‘Little  Cado.’  

Unfortunately, it is exceedingly difficult to come across these varieties at a local nursery outside of California, Florida, and Texas. There are some online sources for small, established trees that will send them through the post, so don’t despair. For those bound and determined, there are options, but for anyone who wants to experiment, there are always grocery store avocados that come complete with viable seeds. More on that below.

How to grow an avocado indoors

There are two ways to grow your own avocado tree. Avocados can be grown from an avocado pit harvested from a grocery store avocado, or they can be grown from nursery stock. An interesting fact to bear in mind is that nursery-grown avocados are not grown from seed, but are cloned from mature trees. What that means is that they will mature at a much more rapid rate than a seed, which will spend many years developing.

Start a seed in water like this.

Growing an avocado from seed

Growing an avocado from seed is easier than most people imagine. The first thing to do is to rinse the seed clean. Next, using three toothpicks, suspend it, broad end at the bottom, over a glass of water filled so the seed is submerged to around an inch, with the top exposed to air. Place the glass in a warm spot out of direct sunlight. 

After six weeks, roots and a stem shoot should begin emerging from the seed. (If nothing has happened after eight weeks, toss your seed out and try again with another one.) Continue to change out the water in the glass and wait until the stem is between six and seven inches long. Cut it back to three inches and wait for it to sprout leaves. 

Once you have dense roots and healthy-looking leaves, it’s time to transplant into a pot. Find a pot ten inches or larger in diameter with good drainage holes– terra cotta is a great choice for avocados. The most important thing to provide an avocado plant is good drainage. They have very shallow root systems and can easily be killed if the roots are saturated for more than a couple of days. 

Use a sandy potting soil designed for cacti or citrus– something loose, fertile, and well-drained. Some coarse stones placed in the bottom of the pot can be helpful with ensuring good drainage, too. Loosely fill the pot almost to the top with potting mix and hollow out a hole deep enough for the avocado seedling’s roots. Spread the roots out and gently pack soil around the pit, leaving the top of the seed above the soil line. Water gently until water runs from the drainage holes, wait for it to stop, and then place the pot into a drainage dish in a south-facing window.

From here on, the instructions will be the same as if you started with a nursery-grown tree.

Growing an avocado from a young tree

Growing an avocado tree purchased from a nursery or online is obviously going to be easier than growing from seed. However, these are delicate plants that require very specific conditions to flourish and eventually bear fruit. 

Plants that arrive through the mail must be planted immediately, while nursery plants may be fine in the pots they come in, if they are appropriately sized. The larger the pot, the likelier the plant will start growing vigorously right away. 

If you must do so, plant or transplant the young tree into a large pot with good drainage. Use a potting mix designed for cacti or citrus and never bury the trunk any deeper than the part that flares out at the base. If a young nursery tree is root-bound, rough up the root ball a bit to untangle or fray roots before planting. Place the pot in a location where it receives full sun.

Caring for avocado trees

Temperature and Light

Avocados are sensitive plants with some very specific requirements. They do best in warm temperatures, ideally between 60 and 85 degrees fahrenheit– which makes them excellent indoor plants. They enjoy full sun and may benefit from a bit of supplemental light during the winter months. 

Water

Avocado trees cannot handle too much water.  In fact, overwatering is the number one cause of death for potted avocado trees, so don’t overdo it, and always check the moisture level of the soil before watering. This is particularly important in the first year as the tree is getting established. Yellowing leaves are usually a sign of overwatering. If it looks like your avocado tree is yellowing, let it dry out for a few days.

The best method for watering an avocado plant is to do a deep soak once a week, or as soon as the leaves show signs of wilting. The best policy is to check in every day with a plant to see how it is doing. Watering in winter can be especially problematic, as the water in the soil evaporates more slowly in cooler months, any excess can result in root rot. Once this begins, it is very difficult to save the plant, so best to avoid it by watering sparingly.

Another problem avocados in both pots suffer from is the accumulation of salts in their soil. If the leaves are turning brown and curling/drying at the tips, it’s a sure sign of this. There are two ways to deal with mineral buildup in soil. The first is using only rainwater to water your avocado tree. If this isn’t an option, then use distilled water to flush the soil by letting water run freely into the pot (over a sink) while it drains continuously for several minutes. 

Pruning and Staking

Cutting back plants can feel mercenary, but the truth is that it stimulates bushy new growth that is stronger and more robust than single-stemmed growth. Always use tools that are sharp and cleaning order to avoid introducing bacteria or disease. 

When an avocado seedling reaches twelve inches or so, trim the tip and top leaves off, cutting just above a growth node. This will encourage healthy lateral growth. Once lateral stems are six to eight inches long, trim the new growth at the tips off.

Pruning in this fashion is only advisable in the first year as the shape of the tree is being established. After that, only prune once a year in autumn or winter when the tree isn’t adding much new growth. Once a seedling is over two feet tall, staking it will help to support its weight. A piece of bamboo makes a perfect stake, just drive it into the soil near the base of the plant and tie the stem loosely with a twist-tie or piece of twine. 

Fertilizing

In the first year of an avocado tree’s life, a fertilizer for citrus trees can help it establish. Apply a citrus fertilizer as directed every couple of months for the first year, but don’t do it too frequently or heavily. Avocado trees benefit from ten percent nitrogen, phosphorus, and potash along with six percent magnesium.

Spraying with copper, zinc, manganese, and boron (trace elements) every couple of months in spring and summer for the first four years will help your tree get to the point where it can bear fruit. When your tree begins to set fruit, increase potash fertilization to fifteen percent.

Moving potted avocados outdoors

Unless you live in Southern California, Florida, Hawaii, or deep Southern Texas, there isn’t much change of leaving an avocado outdoors year-round. However, as long as your summers are warm and sunny, you should be able to set your avocado trees outdoors through the warm months.

For a potted avocado that has never seen the light of day directly, break it in gently by first placing it in an outdoor location that receives filtered sunlight. After a day or two, move it to full sun and it will likely thank you with vigorous growth. Pay closer attention to it outdoors than you might normally, as the soil can dry out much faster in the open air.

There are a few fungal diseases and pests that can affect an avocado tree, none of which are very common. If you detect anything afflicting the leaves or fruit of your avocado tree, diagnose and treat the issue as soon as possible.

When will my avocado bear fruit?

The honest truth is that the odds of an indoor avocado bearing fruit are not great– it’s by no means impossible, but growing avocado fruit is a long term commitment. That said, the growing method used will have the most significant effect on when indoor plants bear fruit.

Avocados grown from seed will not bear fruit until they’re at least a decade old, and may take even longer than that. Trees planted from a nursery will produce much more quickly, beginning at about three or four years old. While it may be tempting to go straight to a nursery grown avocado, consider growing from seed to learn how to care for one first. That way, when your nursery tree arrives, you’ll be fully prepared to give it the care it needs to thrive. 

Harvesting Fruit

When your plant begins to set fruit, it may set a huge number at first. It will most likely drop a large number of these fruit, so don’t panic–it’s perfectly normal. Additionally, unlike many fruit trees, avocados do not ripen on the plant. Once the fruit reaches a mature size, pick one and let it sit on a shelf for a few days. If they shrivel up or never become soft, it isn’t time. Pick another couple of fruits every week until they ripen. At that point, pick as you desire and leave what you don’t want on the tree. 

Whether or not your avocado tree bears fruit, you will have a unique and beautiful houseplant that will impress your guests. However, if you take your time and treat your tree right, you will be rewarded with the rarest of homegrown fruits, avocados. Which anyone would agree is well worth the effort.  

Sources:

  1. http://www.umich.edu/~ac213/student_projects06/student_projects/lfc/Avocado.htm
  2. https://www.slowfoodusa.org/ark-item/puebla-avocado
  3. https://www.finedininglovers.com/blog/food-drinks/avocado-varieties/