I've got a windowsill with a number of avocados growing from seed (I'm in Rural Auckland - so US Hardiness zone 9b, heading towards winter) - A couple of my plants have just started to poke out the top of the Avo (ie stems, not roots).

For now, am I better off leaving them inside my house, which would have a more constant temperature of around 18-24 degrees c, or putting it into my unheated polytunnel which will get warmer during the day, but much cooler at night. I'd imagine 8c - 35c [ eventually going down much colder - I expect temperatures are a bit marginal in winter here ] and with greater humidity and probably more overall light ?

Also, if i'm moving them to the polytunnel can I transplant them now, or am I better to wait until they are 15cm's or so tall ?

1 Answer 1


Avocados are a subtropical species that like high humidity and a climate without even mild frost. They prefer deep, well drained soil that has a pH around 6.2 (slightly acidic).

Since they don't like any temperature below freezing, growing them indoors is probably best during winter in your zone. Once you are sure no freezing will occur you can move them outside as long as they are sheltered from any wind to prevent low humidity.

As to your transplanting question: transplanting causes stress, which you want to minimize as much as possible. The best time to transplant is late fall after leaves have fallen or early spring before new growth. Best time of day is late afternoon and during a cloudy, non-windy day if outside. Disturb the root ball as little as possible and make sure it stays moist. Water the plant well after transplanting. After transplanting to a new pot, wait a few days before moving the pot outside. Orient the plant so it faces the same direction relative to the sun as before the transplant. In general, the younger the plant, the better it deals with the stress of a transplant.

Some problems you may eventually see:

--Purple or brown leaf discoloration may indicate a spider mite infestation.

--Yellow or dropping leaves may indicate overwatering/root rot.

Be aware that avocados can grow pretty big (60' tree for Hass Avocado), so re-potting and moving them may eventually pose problems.

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