Gadenin日本語Get the appCheck three things every time you walk past
You do not need a formal inspection routine. Three things looked at in ten seconds catch nearly everything: the base of the stem where it meets the soil, the undersides of the newest leaves, and the angle the plant is standing at compared with yesterday. Everything serious announces itself in one of those three places first.
Once the bud is visible, add a fourth: the back of the head. That is where the trouble of the late season lives, from birds working at the seed to mold settling in behind wet petals.
| Where to look | What you are checking for | How often |
|---|---|---|
| Base of stem | Softness, dark staining, gnaw marks | Every visit |
| Newest leaf undersides | Aphids, stippling, mildew bloom | Every visit |
| Standing angle | Any new lean since yesterday | Every visit |
| Back of the head | Bird damage, damp, mold | Daily from petal drop |
Wilting: the same symptom, four different causes
A wilting sunflower is the symptom people react to fastest and misread most often. Wilting at midday in hot sun with firm soil is simply the plant closing down for a few hours, and watering it does harm rather than good. Wilting in the morning, or wilting that does not recover by dusk, is genuine and needs a cause found.
The test that separates them costs nothing: push a finger four inches (10 cm) into the soil beside the plant first thing in the morning. Damp soil plus a wilted plant means the problem is at the root or in the stem, not in the watering can.
| When it wilts | Soil at 4 in (10 cm) | Cause | What to do |
|---|---|---|---|
| Midday only, recovers by evening | Damp | Normal heat response | Nothing |
| All day | Dry and dusty | Genuine drought | Deep soak, then mulch |
| All day | Damp or wet | Root rot or stem damage | Check the stem base, improve drainage |
| Suddenly, one side only | Either | Root plate torn by wind | Stake and firm the soil back |
A plant that wilts, recovers, then wilts again a day later with damp soil almost always has a damaged or chewed stem at ground level. Clear the soil away and look before doing anything else.
Reading the leaves
Sunflower leaves are large and change color readily, which makes them a useful gauge. What matters is where on the plant the change is happening. Old lower leaves yellowing and dying as the season goes on is the plant recycling nitrogen into the head, and it is entirely normal from bud stage onwards.
New leaves at the top changing color is the signal worth acting on. Pale new growth means the plant is running short of nitrogen while it still needs it; distorted or crumpled new growth almost always means insects rather than nutrition.
| What you see | Where | Likely cause | Action |
|---|---|---|---|
| Yellowing, drying | Lowest leaves only, late season | Normal senescence | Remove them, nothing more |
| Pale green all over | New growth | Nitrogen short | One balanced feed, only before bud stage |
| Crumpled and curled | Newest leaves | Aphids underneath | Wash off with water, check again in three days |
| Pale stippling, fine webbing | Mid and upper leaves | Spider mites in hot dry weather | Spray undersides with water on dry mornings |
| White powdery bloom | Older leaves first | Powdery mildew | Strip affected leaves, improve air movement |
| Dark spots with yellow halos | Lower leaves upward | Leaf spot in wet spells | Remove leaves, avoid overhead watering |
Watching the stem and the standing angle
The stem is the part that decides whether you get a flower at all, and a lean of even ten degrees that was not there the day before is worth investigating immediately. It means either that the root plate has moved, or that something has weakened the stem at ground level.
Look for a soft or discolored patch at the base, gnaw marks from voles or rabbits, or a hole with sawdust-like frass at the edge, which means a borer inside the stem. A plant that has started to lean can be saved if you stake it the same day; left a week, the tear opens further with every gust.
- Sight down the row Stand at one end and look along the line of stems. A plant out of line shows up instantly, far more reliably than looking at each plant on its own.
- Push the stem gently Rock it an inch (2.5 cm). If the soil around the base moves as a plate, the roots have torn and it needs staking and firming today.
- Clear the soil at the base Scrape an inch (2.5 cm) of soil away all round. Chew marks, softness or a bored hole are all obvious once the soil is off, and all invisible with it on.
- Feel for softness Squeeze the bottom four inches (10 cm) of stem lightly. A healthy stem is firm and springy; anything that gives under thumb pressure is rotting inside.
After a storm, walk the row the same day. Firming soil back around a plant that has just shifted works; doing it three days later, once the torn roots have dried, usually does not.
Watching the head from bud to harvest
Once the bud appears, the head becomes the thing to watch, and it moves through a predictable sequence you can date. The bud swells and shows color, the ray petals unfurl over two or three days, the disc florets open from the outside in over about a week while pollinators work them, then the petals fade and drop and the back of the head begins to change color.
Knowing that sequence lets you time everything else. Birds arrive when the seed starts to fill, not when the flower opens. Mold appears on a head that stays wet after the petals drop. And the cut for seed comes several weeks after the last petal falls, not at petal drop itself.
| Stage | What it looks like | What it means for you |
|---|---|---|
| Bud showing color | A sliver of yellow at the tip | Last chance to stake and switch feed |
| Petals unfurling | Ray petals opening outward | Water without fail through this stage |
| Disc open, bees working | Central florets opening ring by ring | Pollination happening, leave it alone |
| Petals fading | Ray petals browning and dropping | Seed starts filling, birds take notice |
| Back of head yellowing | Green back turning pale yellow | Two to three weeks from harvest |
| Back brown, bracts dry | Back brown, neck bent | Ready to cut |
Record the date the first petal opened and the date the back of the head first turned yellow. The gap between those two is remarkably consistent for a given type in your garden, and it lets you plan bird netting and harvest a fortnight ahead.