I was at the grocery store yesterday, shopping for some vegetables, when I glimpsed a small stack of cherimoyas, or custard apples, in the tropical fruit section of the produce department. This reminded me of my own cherimoya plants that I started last year as an experiment in growing tropical fruit in the Pacific Northwest.
Last August, I posted a description with many photos of the process of planting seeds taken from the fruit.
Let me summarize the events of growing cherimoyas from seed.
- May 3, 2010: Extracted seeds
- May 3, 2010: Soaked seeds for 3 days
- May 5, 2010: Planted seeds
- June 20, 2010: First sprouts. Move plants outside
- July, 2010: Transplant healthy seedlings into single pots
- August 11, 2010: All seeds sprouted; plants were healthy and at least 5″ tall
- August 20, 2010: Begin moving plants inside
- September 10, 2010: All plants are moved inside
- Novemeber, 2010: Plants began wilting and drying
- January, 2011: 2 plants lose all or most of their leaves
What Was Sort of Going through My Mind
Because this has always been a casual experiment, I decided to introduce variables into the pots, in each of which were 2 plants. I assumed, from experiences with my outdoor gardening, that the most important factors were exposure to light, watering and temperature.
As soon as the seedlings were sturdy enough, I transplanted the healthiest ones into larger pots. This gave me 5 pots with 6 plants.
Regulating Light Exposure
During the summer, I kept all the pots outside. The days were long and hot, temperatures steadily around 70-75 degrees Fahrenheit. Nights dipped as low as 50 degrees toward the end of summer. By late August, it appeared that the plants were no longer growing.
So I moved a couple inside and placed them on the windowsill in the kitchen, a west-facing spot that receives the most sunlight in my apartment.
By late September, I had moved all the plants inside, as the autumn showers were beginning to discourage the plants from growing, it seemed.
Before they sprouted, I watered the pots of soil once a week. I intended to keep the soil moist but not to drown the seeds. Cherimoyas need well-draining pots and will suffer from over-watering. As soon as they sprouted, I moved them outside. In addition to watering them once a week, when it rained, I allowed the plants to soak up all the precipitation. During the hottest peak of summer, while temperatures reached the 90s, I watered them twice a week.
The primary variable in watering occurred during the transition of moving the plants inside. The first batch to come in received less water, protected from the Pacific Northwest rains that marked last summer’s mild August. They remained healthy while those outside receiving more water lost leaves or began to fade.
After moving all of them inside, I watered them less. By autumn, I was watering them once every two-and-a-half weeks. By winter, I was watering them once every couple months. Since November, I have watered them twice.
In the beginning, all the plants remained in the same climate, so temperatures were even for all. As Seattle warmed, the outside temperature–and thus the inside temperature–became less polarized.
During July and August, the plants were just as warm as my peppers, eggplant, tomatoes, squash and other summer plants. It was during these two months the plants grew best.
When I brought a few inside, I decided to create a greenhouse for two of the pots. For one, I turned a plastic juice container upside-down. For another, I cut the bottom off a two-liter bottle, removed the label and covered the plant with it.
By far, creating these two greenhouses had the most noticeable effect on the stamina and health of the plants. The juice container was fogged, thick and see-through white, while the two-liter bottle was transparent, thin and clear. Of the two, the plant under the two-liter bottle was the healthiest and greenest of all the plants. In fact, it remained green all through the winter, the only one to do so.
The plant underneath the juice container, on the other hand, eventually dried. I decided to remove it entirely in December. The plant still looks as it did then.
As autumn and winter passed, the temperature in my apartment has been more polarized, marked by cold nights and warm days. The plants have showed little to no change since autumn, having slowly browned and hardened, except for the one under the two-liter bottle.
The State of the Plants in the Winter
The plants look dead, as all the deciduous trees do around here. One remains green and vibrant, though. I am curious to see how this affects its growth this spring. Maintaining a more even temperature, as I’ve done with the two-liter greenhouse, has made such a difference that I ought to try to make sense of it.
Chermimoyas are native to the Andes. Looking at the annual weather pattern of the area, I see an average high of mid-70s in the summer and an average of upper-50s in the winter. In other words, there is little variance in the temperature throughout the year. Independent references informed me that cherimoyas need a cool period, but will suffer from frost, which is why they are always grown commercially in frost-free zones (e.g., southern California, southern Spain, Mexico).
In addition to the stable but varying temperatures, the greenhouse provides some moisture in the otherwise dry air of my apartment. Being so green, the added humidity no doubt contributes to keeping the leaves full of chlorophyll.
Yet, none of the plants have been exposed to frost and all of them are clearly dormant. I will have to wait for spring to see what happens next.
If I could go back and start all over again, I would have another two-liter bottle and remove it as the other plants began shedding their leaves. I have some seeds from last year. Perhaps I may germinate some more and try it again.
This has entirely been a new experience for me. Most of my information has come from the Center for New Crops & Plant Products at Purdue University.
The California Rare Fruit Growers, Inc., page on cherimoyas is another great resource.
There’s a very helpful page about growing cherimoyas in The Encyclopedia of Fruits & Nuts available on Google Books.
Most references say that cherimoyas can be transplanted outside once they’re about two years old. Doing that in this climate would surely kill them. I still don’t know if they’ll make it another year. Whether they do, it’s hard to imagine, at least now, that they will even flower.