Hartley Magazine

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Grow Your Own Avocado – A perfect winter greenhouse project

Most of us have tried to grow an avocado (Persea americana) tree from seed. Although an avocado plant can be grown in any large, indoor room, it’s also does well in a heated greenhouse. Both heat and humidity must be kept fairly high for an avocado tree to thrive.

Starting the pitTo grow an avocado from seed, start by half-submerging a well-rinsed pit (pointy end up) in a container of water, with the pit supported by three toothpicks stuck into its sides. After about six weeks, the pit will split in half and a root will start growing downwards into the water. Then a stalk will start sprouting upwards.

After planting the seedling in a good-quality soil and keeping it warm and moist, the assumption is that the avocado should grow fine from here on. it often wilts and dies if not kept warm and moist. For most beginners, a gangly stalk grows straight up until it’s about four or five feet tall. This is hardly the lush, subtropical plant imagined.

The trick to producing an attractive, bushy avocado tree is to snip off the growing tip (the top two or four tiny leaves) after the plant is about 12 to 18 inches tall. This causes the stalk to produce lateral branches. By snipping off the growing tip on each branch, a plant with a nice, bushy form can be obtained, as long it receives adequate sunlight.

But don’t expect this plant to give you a bountiful crop of avocados. Avocado plants grown from seed are usually sterile, or at best they set fruit that is nothing like that of the parent plant. To get the avocados you know and love, you must graft a fruiting avocado branch onto your pit-grown tree.

To do this, let the stalk grow without snipping off its tip until it’s about two feet tall. This should produce aGreenhouse avocado stalk strong enough for grafting. The branch you use for grafting should come from a propagated avocado plant. The new branch should be the same diameter as the stalk onto which it will be attached. Simply cut a v-notch in the stalk and cut the end of the branch to fit the notch. Then secure the branch in place with grafting tape or a suitable substitute. Make sure the bark on both pieces is precisely aligned to enable the flow of sap, and minerals through the vascular tissue. Now just water the plant and wait for it to grow. If the graft takes, it will start to grow, and in a few years you should get avocados. Snip off any branches that sprout below the graft because they will absorb the sap that should go to the new branch and the new branch will die.

  • While this is awesome, my first question is, has anyone actually done this and produced avocado fruit in Canada?

    I’m looking into creating a 4 season greenhouse inside another, specifically to create a tropical zone, in zone 3 in Canada

  • Debbie

    Hi Steve and Rob, It looks like this post is old but I’m still hopeful that one of you will see it and wouldn’t mind including me in your discussions. I am passionate about figuring out how to grow a fruit bearing avocado tree in NJ by somehow simulating the growing conditions in a greenhouse environment. ~Debbie M in NJ

    • Marisa Sigano Kosinski

      Hi Debbie, if you see this, I am also trying to grow Avocado in. Nj greenhouse. I’m not sure how old my tree is now. Never got flowers yet.

  • Hi! I also want to join the discussion. I live in California anticipating a future north in Washington state where they do not grow. A greenhouse is essential if it’s going to work. Let’s keep this thread alive. Rick, how’s your progress?

  • Pamela Dykier

    I have an Avocado tree that I grew from a seed at my desk in a medical clinic. It soon became to big for the desk and I moved it home. My tree is about 4 1/2 ft tall and too heavy to move on my own to water. it like a soaking with complete drainage. I live outside of Portland Oregon and have no where to keep it with winter coming. Not sure what to do. Do commercial Green houses rent space for a little tree for about 6 months out of the year??

    • Hartley Botanic

      Roger tells us – I have four avocado trees in my greenhouse. One is eight to nine feet tall. All were grown from seed. The problem as I understand it, is that trees grown from seed are sterile. To get fruit you will need to cut the tree and graft a branch from a fruiting tree in its place. If the graft takes the branch will bear fruit. The graft can be as simple as lopping off the stem when the tree is a foot tall and setting a bud or a small branch in its place. When doing so, be sure to line up the cambium layer so the sap will flow into the branch and the branch will grow. Two of my trees have been grafted and are growing well.

      As for growing in a greenhouse, Winter temps in my Rhode Island greenhouse get down to about 45 degrees on cold nights, although in a really cold spell the aluminium door frame froze on the inside. All the avocado survived but two trees dropped their leaves. An avocado will survive quite well indoors, but you should put a large container under it when watering to keep the water off the floor.

      I don’t know of any outfits that rent greenhouse space. It is too easy to import disease into a greenhouse. Maybe you have a friend with a greenhouse who could help. An alternative might be to put the tree in your garage and build a plastic mini-greenhouse around it with an LED grow light over the top of the tree to give it enough light. You might have to keep the garage door closed on really cold days.

      • Pamela Dykier

        Thanks for all the great info! Hartley Botanic is a great resource! I will bring her in for the winter, last winter she did not like it much. She dropped leaves some turned brown. She does much better outside. She is about 4 feet tall with branches. she prefers to have a good soaking once a week, I let the water drain through and out. Inside she often ended up sitting in some water and I think she hated that. I am not sure where I would find a fruiting tree here in Oregon. My plan was to drive her to So. California and plant in my son’s yard, just cant get there this year. thanks again.

  • Jennifer brown

    I live in Sioux Falls, South Dakota and I’m growing a avocado tree by seed and i wanted to keep indoors for the winter and and now it’s spring and summer here in South Dakota I wanted to grow indoors all year long and our winter gets very cold. Please let me know what to do with my avocado tree it’s starting to sprout now.

    • Hartley Botanic

      Reply from Roger Marshall – You can grow indoors all year round in moderate to bright sunlight. I grew an avocado for a few years indoors in a New York apartment! Avocadoes like warm temperatures just like people. If it warms up outside and you want to move it outdoors, do so. Just remember to move it back indoors before outside temperatures drop to around 50 degrees F. If you move it outside, do NOT put it in direct sunlight. It probably has had shaded light indoors and putting it out in direct sunlight will burn the leaves. They may well fall off, but the plant will regrow them to suit direct sun. Each time the leaves drop the plant might weaken a tad, so try not to drop leaves too many times.
      If you grow in a pot, as the plant grows upwards the roots must grow downwards to sustain the growth, so remember to check the root system once a year or so. You may need to repot into a larger pot in fall or during the winter months.