Please don't think I'm joking, this is not a wind up or an early April Fool. Pineapples really are one of the most amazingly easy, reliable and remarkably trouble free plants to get to crop. Honest. I've written about them before but still only a few people seem to have tried them yet. I guess they seem too exotic, or maybe the old boys made it sound all too complicated or hinted one needed a stove house the size of Kew's. Nope pineapples just need to be kept frost free. That's it, no more complicated than citrus, indeed easier.
But that is not the half of it. All shop pineapples have the problem of being transported vast distances so they can never be picked freshly ripe. So, as with so many other fruits, the home grown is the only one that can be eaten at it's very best. And of course there is also the matter of size. Home grown pineapples can be got to grow very large, I consider six pounders fair, eight to ten pounds is easily achievable. (In the past twice as much was attained -but only with certain varieties.) And then the sweetness, flavour and texture. No bought fruit has ever tasted as good, nor had such a creamy, almost vanilla flavour, without either excessive acidity or any pear drops overtone . I have travelled extensively and even in the tropics I have rarely had as good a pineapple as I can grow here in Norfolk -believe me.
So here's how you can do the same. Pineapples want to grow and fruit, it just happens. All you have to do is keep them warm and although they prefer very warm they will survive cool conditions if dry and even survive dry cold for a short time. Any frost or damp cold and they rot quickly so they are not at all adapted to outdoor culture here in the UK, even in the milder counties where such as Agaves, date palms and tougher bananas survive.
Now I have one trial specimen growing indoors in a floating pot of watercress but it is not thriving to say the least. It's water is not warm but never gets very chilly as it's in my frost free polytunnel. This is however an extreme case and be warned that pineapples normally loathe water logging when cold, its just this poor dwarf was started off like this and has somehow endured. They will happily survive months of almost total aridity that would kill most plants and that is the way to keep them through winter unless you can keep the heat up.
Pineapples do not take up much height as the plants only reach about a metre tall by a metre and a half wide at the biggest and are usually only half that when grown well enough to give really good fruits. However the ends of the stiff leaves are pointed and many of the choicer varieties have razor sharp saw tooth edges that will slice flesh! (These are difficult to find as not being very popular with the growers but do have the finest flavours.)
As with most plants; if you crowd them, cramp them in small pots or check them in any other way then they bolt and flower early with only small fruits. However they will still crop anyway. If you can do no more than keep one just alive in a small pot it will never make a prize fruit but it will form a tiny one, a miniature, sort of more of a pineapple chunk.
Unless you can find a supplier the first plants you grow will have to come from the crowns of bought fruits. These will crop for you within about three years of starting. However once your first plants grow they will throw side shoots and these can be removed to make stronger growing plants which fruit with only two years growth. These side shoots also make for the biggest plants and fruits if detached and grown on but will also crop if left on the original where they perform less well forming a secondary 'ratoon' crop.
Starting with a crown: Choose a fresh green crown on a healthy fruit making sure the centre is alive not dead or rotting. try pulling the smallest inner leaves -if they come out easily then reject that fruit. (In extremis any bit of the crown or stalk can be forced to sprout.) Having chosen a good one then grasp it firmly and twist it out of the fruit. Tidy off any very ragged torn fruit flesh but leave as much of the tougher core as possible. Put the crown in a warm sunny dry spot for a week to dry the wound. A week or so later pull off the dried lower outer leaves, in order, carefully. You will probably find small roots already there. (If not don't worry.) Now pot in a very open sterile gritty compost and keep warm preferably with bottom heat, or similar. Keep the compost barely moist and the top dryish with a light misting on sunny days.
Once your crown gets going you can pot it up into a larger pot the first summer and then again the next spring and summer. By then it should be large enough to flower and fruit the following spring when it will stop growing much bigger. I prefer the fewest stages to reduce checks. Initially once well rooted the best of mine go straight into permanent tubs with soil warming cable underneath for the champion plants. But to save space and get more fruits others are potted in litre pots the first summer to over winter, going up into 2-5l pots the next spring and then 10-20l ones that summer to fruit the next year. Or several are crammed for their fruiting year in a 30-40l tub which works well if they are large plants done growing already. (At repotting any dead leaves can be pulled away.)
Their compost needs to be very free draining and I use a mixture of sieved garden compost, leaf mould, composted bark, sand and grit with a little bone meal, soot and wood ashes. Other than drainage the crucial thing I find is to keep down the lime level otherwise they become chlorotic though a small amount is no problem. During the middle of the growing season they benefit from regular but light liquid feeding with a soot, borage and comfrey tea and frequent seaweed mistings. Indeed frequent mistings is very effective and seems to be their preferred method of receiving water, rain not tap and pre-warmed. In summer they are happy sprayed hard every day which helps remove pests. (Very few pests bother them, mealy bug seems to be the only regular trouble.) In winter I keep mine completely dried off on top, and put an extra plastic sheet over their top as an extra insulation and to exclude drips from the roof. In spring and autumn be cautious, do not start watering too soon unless sun and warmth are in abundance. Equally in autumn err on the side of drought unless the conditions are still buoyant.
If you have bottom heat and a well heated greenhouse to room temperature conditions then pineapples will grow throw the winter and can be given a modicum of warm water misting occasionally just to prevent desiccation. They are thus also suited to warm conservatories where the demands of most plants for higher humidity does not suit us or our furnishings. And they do not need much light to just grow. In summer pineapples prefer the diffused light of plastic to bright clear glass sunlight. Amazingly some even grow and crop in quite heavy shade at the back of all my other tender plants though of course then they take longer to throw smaller less sweet fruits -but they do! However the best crops need plenty of light.
The plants will flower and fruit when they are ready but if you want to force them then they respond to smoke. A good dose of smoke (I use my bee smoker full of old sacking) and they will come into flower. (They used to drop a tiny piece of calcium carbide, which with water gives off the inflammable gas acetylene, directly in the crown of a big plant to cause it to come into bloom.) If smoked about February/ March big plants should ripen their fruit that year about Christmas time. Which when it works is neat.
The first sight of flowering is a thistle appearing in the centre of the plant which rises and swells into a miniature pine cone like mini-pineapple, often crimson, on a stalk. This then swells more and protrudes lilac purple flowers a half dozen or so at a time over the next week or so. (These need no pollination as we do not want seeds and are not self fertile but could be crossed with another if you so wished) I cut back on the misting while the flowers are out to prevent their being rotted away.
Once the flowers are set the fruit slowly swells over the following months, eventually it colours (not all do as some rare sorts are green when ripe) to a golden yellow. Do not leave it to go over on the plant but cut it with a bit of stalk when there is still just some green left. Hold back on all the water and misting once any colouring appears. I find a mulch of ripe banana skins accelerates the pineapple's ripening. (And is another way to make other plants bloom earlier or bolt if you are not careful as I found out.)
Once your fruit has gone you can reject the original plant, cut it back to the roots or just leave it to mature side-shoots which can be detached or left in place for a smaller fruited ratoon crop. In the latter case it improves the size if the old plant and the bases of the shoots can be earthed up around to encourage basal rooting. And almost any bit of the old stalk can be cut and struck to make new plants but these are slower to crop than the bigger side-shoots.
And be warned, once you eat your first home grown fruit you will become addicted to growing them. The thrill of the flowering, the ripening and the harvest are all enjoyable and satisfying but the pleasure from eating a home grown pineapple is so divine one is never enough.