Gadenin日本語Get the appWhat the tree is actually doing
Understanding one fact makes guava care simple: flowers form on shoots that grew this season. Every flush of new growth is a potential crop, and anything that stops the tree pushing new shoots also stops the fruit. So the aim of routine care is not to keep the tree tidy or restrained. It is to keep it producing new wood through the warm months, then to keep that wood well enough supplied with water that the fruit it sets actually fills out.
In a frost-free climate a mature guava will do this more or less continuously and can give you two crops a year. Where the tree is potted and overwintered indoors, it runs on a single cycle: a strong flush after you cut it back in spring, flowers on that flush, and fruit through late summer and autumn.
Water: the one thing it will not forgive
Guava is drought-tolerant in the sense that it survives dry spells. It is not drought-tolerant in the sense that matters to you, because a tree that dries out while fruit is swelling will shed that fruit within days, and the fruit it keeps will be small, hard and gritty. The critical window runs from petal fall until the fruit reaches full size, roughly three to five months depending on temperature.
In the ground, water deeply once or twice a week in hot weather rather than lightly every day, aiming to wet the soil to a foot (30 cm). In a pot, check daily in summer by pushing a finger two inches (5 cm) into the mix; water when that depth is dry, and water until it runs freely from the base. A fruiting guava in a twenty gallon (75 L) pot in high summer can need watering every single day. Through winter, cut back sharply. A tree kept at 50 to 60F (10 to 16C) indoors wants the mix barely moist and no more, perhaps once every ten days.
| Sign | Likely cause | What to do |
|---|---|---|
| Leaves limp at midday, firm again by evening | Normal heat response | Nothing; check the mix before assuming drought |
| Leaves limp in the morning | Genuine drought | Water deeply now, then set a shorter interval |
| Small fruit dropping in a wave | The tree dried out one to two weeks ago | Restore steady watering; the remaining fruit will still fill |
| Yellowing lower leaves, soil constantly wet | Waterlogging | Stop watering, check drainage holes, repot if the mix has collapsed |
| Leaf tips brown and dry, edges curled | Salt build-up from feed | Flush the pot with plain water until it runs clear from the base |
Feeding for new growth, not for size
Guava is a fairly hungry plant compared with most subtropical fruit, and a potted one is dependent on you entirely. Feed only while the tree is in active growth. Start when new shoots appear in spring and stop six to eight weeks before you expect cold weather, because soft late growth is the part that frost destroys.
Use a balanced fertilizer through the first flush, then shift to one lower in nitrogen and higher in potassium once flower buds appear. Guava is also notably prone to zinc and iron deficiency on alkaline soil, which shows as pale new leaves with green veins. A foliar micronutrient spray applied to new growth twice in the first half of the season corrects it faster than anything applied to the soil.
- First flush, after pruning As new shoots reach two inches (5 cm), begin a balanced liquid feed every two weeks, or work a slow-release granular fertilizer into the top of the soil. This flush is the wood that will carry the crop, so this is the feed that matters most.
- At flower bud stage Switch to a lower-nitrogen, higher-potassium feed every two weeks. Continuing heavy nitrogen here gives you a leafy tree with few flowers, which is the commonest reason a well-watered, well-fed guava does not fruit.
- While fruit is swelling Keep the potassium-rich feed going at the same interval and be strict about watering. In a pot, add a monthly dose of a general trace-element mix, because repeated watering leaches micronutrients out of a container far faster than out of open ground.
- After the last pick Stop feeding entirely. The tree needs to harden its wood before cold weather, and any feed applied now works against that. Resume only with next season's new growth.
Keeping a potted tree productive year after year
A container guava declines for predictable reasons: the mix collapses, the roots fill the pot, and nothing you pour in reaches them. Repot or root-prune every second year at the start of the growing season. If you want to keep the same pot, slide the tree out, cut the outer inch (2.5 cm) of the rootball away all round with a bread knife, tease out the base, and return it with fresh mix. Do this in the same session as the annual hard prune so that top and roots are reduced together.
Move the tree outdoors as soon as nights hold above 50F (10C), and harden it off over a week in dappled shade before it takes full sun, or the overwintered leaves will scorch. Bring it back in before the first frost, and expect it to drop a proportion of its leaves within a fortnight of coming indoors. That is a light response, not a problem. Keep it as bright as you can, keep it cool, and keep it dry.
Do not feed an overwintering guava indoors. Warmth plus fertilizer plus weak winter light produces long pale shoots that snap and carry no fruit, and you will be cutting them all off in spring anyway.
The records that make next year easier
Guava responds to care on a delay, and the delay is what makes it hard to learn from. Fruit that drops in midsummer was decided by a dry spell a fortnight earlier. Small fruit in autumn was decided by a feed you did or did not give in spring. Writing down four dates a year closes that gap: the date the first new shoots appeared, the date you saw the first open flower, the date fruit drop happened if it happened, and the date of your first pick.
Alongside those, note how often you watered in the hottest fortnight and what you fed. After two seasons you will be able to point at the exact week where the crop was made or lost, and you can shift your watering interval a few days earlier the following year rather than guessing.