Course 05 · Quiz 1 of 2 · Nutrients, labels, and sources

Quiz 1: Nutrients, labels, and sources

What nutrients do and why a small pot runs low, reading a label's analysis and directions, and how liquid, solid, organic, and mineral feeds release, applied to decisions about what to feed and how.

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10 questions, each worth one point. Some ask for one answer; others ask you to select a stated number of answers.
For questions with several answers, each correct choice earns an equal share of the point.
Pass with 80%: at least 8 of 10 points.
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Question 1 of 10 ScenarioA friend's north-facing balcony in July: a juniper stands in a back corner, where no direct sun reaches it. Since spring its new shoots have come out pale, thin, and long, its foliage so sparse you can see through it, and some inner foliage has yellowed and dropped. It has had the 8-4-6 at its outdoor line every 14 days since April, its roots are firm with white tips at the holes, its pot dries back between thorough waterings with nothing standing under it, and no pests show. The friend plans to double the feed to green it up.What should the friend do first?
Double the feed as planned, since pale, thin growth shows the feed is not keeping up with itFind it a sunnier spot first, since shade, not a short supply, is what is holding it backKeep the plan and wait, since a juniper's soft new growth is naturally paler than old foliageSpray a dilute feed onto the foliage, since in shade its needles can take the feed in directly
Question 2 of 10 ScenarioThe courtyard in June: the courtyard maple's owner, who keeps a careful record of its growth, wants to know which end of a shoot would show each shortage first, once one is deep enough to mark the leaves themselves rather than only slow the growth. On each of the maple's shoots, the oldest leaves sit at the base, where the shoot began this spring, and the newest at the growing tip. The owner starts with five nutrients a tree uses: nitrogen, phosphorus, magnesium, calcium, and iron.Which two tend to show first on the newest leaves? Select two.0 of 2 selected
Calcium, since once it is built into the walls of a leaf's cells, it stays where it was putNitrogen, since once it is built into a leaf's proteins, the tree cannot take it back outIron, since once a leaf holds it, the tree cannot send it on to the leaves growing abovePhosphorus, since once it is part of a leaf's cells, the tree cannot move it anywhere elseMagnesium, since once it sits in a leaf's chlorophyll, the tree cannot draw it back out again
Question 3 of 10 ScenarioThe west balcony in July: the trident maple, repotted in March into a fresh, coarse mix of akadama, pumice, and lava, has been growing well since May and now gets the 8-4-6 at its outdoor line every 14 days, with thorough waterings from the kitchen tap in between. Helping during one of the owner's work trips, the friend asks why a tree in brand-new mix needs feeding at all, let alone every two weeks, when a garden tree is never fed.Which two facts explain the regular feeding? Select two.0 of 2 selected
Feed must stand in for organic matter, since roots take up most of their nutrients from itEvery thorough watering drains some feed away, since what is dissolved leaves with the waterThe mix supplies very little, since pumice and lava are inert and akadama only holds feedFresh mix holds nitrogen back at first, since microbes breaking it down take nitrogen upIts roots need extra feed to regrow, since they were cut back when it was repotted this March
Question 4 of 10 ScenarioThe small backyard in April: at the garden center, one of the household's two adults turns over a jar of the granules, controlled-release fertilizer 14-8-11, and reads the analysis on its fictional label: “Total nitrogen (N) 14.0%”, “Available phosphate (P₂O₅) 8.0%”, “Soluble potash (K₂O) 11.0%”, and “Phosphate and potash are given as P₂O₅ and K₂O, as on many labels.” Before comparing it with other products, they want its potassium in the same terms.How much potassium itself do the granules hold?
About 5 percent, since a potash figure multiplied by about 0.44 gives the potassium in itAbout 9 percent, since a potash figure multiplied by about 0.83 gives the potassium in it11 percent, since the third number on a label's front is the potassium itself, by weightAbout 13 percent, since potash understates the element, so 11 is divided by about 0.83
Question 5 of 10 ScenarioA front step elsewhere in the example city, in July: an acid-loving azalea grows in a small pot long watered from the city's moderately hard tap. Its root zone's pH read Slightly alkaline in spring, so its owner is moving it to mostly rain-barrel water with some hose water, and since June it has had the acid-loving feed at its line, which the owner plans to keep. A neighbor who feeds a ficus on rainwater with the 14-4-14 powder suggests switching the azalea to it: its numbers are bigger, and it is made for rainwater, which is slightly acidic. The fictional labels give the acid-loving feed's nitrogen as 7.0 percent ammoniacal and 3.0 percent urea, and the 14-4-14's as 1.2 percent ammoniacal, 10.3 percent nitrate, and 2.5 percent urea.What should the owner do about the azalea's feed?
Switch it to the 14-4-14, since a feed made for slightly acidic rainwater suits an acid loverSwitch it to the 14-4-14, since 14 percent nitrogen is more, and more nitrogen acidifies fasterKeep the acid-loving feed as planned, since with no nitrate, its nitrogen tends to lower the pHKeep the acid-loving feed and stir in the 14-4-14, since that way the azalea gets calcium too
Question 6 of 10 ScenarioThe bright window in January, with the heating on: the ficus, which lives indoors all year, is still opening new leaves of normal size and color under its grow light, more slowly than in summer. Its owner mixes each feed in a 1 L (about a quart) jug at the kitchen sink, from the 8-4-6 liquid, whose fictional label gives three lines: outdoor containers, including bonsai kept outdoors, 4 mL per 1 L of water, every 14 days while plants are actively growing; houseplants and indoor bonsai, 2 mL per 1 L, every 14 days in spring and summer, every 28 days in autumn and winter if still growing; garden beds, 8 mL per 1 L, every 14 days.What should the ficus's winter plan say?
2 mL in the jug every 14 days, since under its grow light the ficus grows just as in summerNothing at all until spring, since a tree is not fed in winter, whatever light it gets indoors2 mL in the jug every 28 days, since that line covers an indoor tree still growing in winter4 mL in the jug every 14 days, since the first line is the one that names bonsai in containers
Question 7 of 10 ScenarioA club member's kitchen in August: two 2 L (about half a gallon) cans stand at the sink, each mixed at a line on its fictional label. One, for the azalea by the back door, holds the acid-loving feed at 1 level scoop (1 g) per 1 L of water, so 2 scoops. The other, for the houseplants, holds the 8-4-6 at its houseplant and indoor bonsai line, 2 mL per 1 L, so 4 mL. Reading the fronts, 10-4-6 and 8-4-6, the club member wonders which can is the stronger.Which can carries more nitrogen?
The azalea's can, since by the fronts its feed is 10 percent nitrogen and the liquid only 8The houseplants' can, since 4 mL of 8 percent liquid holds more than 2 g of 10 percent powderThe azalea's can, about twice as strong, since the houseplant line is half the liquid's strengthAbout the same, since each can is mixed at the rate that its own label gives for that plant
Question 8 of 10 ScenarioA friend's maple in late April: at bud break, early in the month, the friend scattered the granules on its pot at the label's rate, 3 g per 1 L of pot volume, lightly covered. Their fictional label reads: “Each granule's coating lets nutrients out slowly for about 4 months at an average root-zone temperature of 21 °C (70 °F). Release is faster when warmer and slower when cooler.” The nights since have stayed near freezing and the days cool, and the mix has stayed moist. The granules still look glossy and full, and the maple's first leaves are just opening. The friend plans a second dose to get them going, but a neighbor says to let the weather do the work.What should the friend do?
Add nothing more for now, since cold slows each coating, and the granules speed up as it warmsScatter the second dose, since in a cold spring the first one will run out before summer comesWater the pot more often, since moisture is what sets the pace at which a coating releasesGive the 8-4-6 too until the granules start, since a cold pot leaves the maple short till then
Question 9 of 10 ScenarioA patio elsewhere in the example city, in July: a beginner's young trident maple stands in a 20 cm (8 in) pot on a bench shaded in the afternoons. Its owner set a ring of six seed-meal cakes on it in May and a second ring of six in June; the cakes' fictional label says one for every 10 cm (4 in) of pot width. Counting the cakes as a gentle extra, the owner has also given it the 8-4-6 at its outdoor line every week; the line says every 14 days. After a warm, wet week, a white crust rims the pot, the leaf edges are browning, and the tree droops in the afternoon, though its pot checks moist and drains freely.What should the owner do first?
Water it more often in the afternoons, since a tree that droops in July heat is short of waterLift off the cakes, stop the liquid, and rinse the pot, since both feeds ran over their labelsStop the liquid but keep all the cakes, since organic cakes release too gently to burn rootsKeep both feeds but rinse the pot each week, since weekly rinses stop the salts building up
Question 10 of 10 ScenarioThe west balcony in early July: apart from the August trip, the owner travels for work about one week in every four and is home the other three; during a trip, the friend comes every second day to check and water. All three trees are healthy, growing, and on the 8-4-6 at its outdoor line, 8 mL in the 2 L (about half a gallon) can every 14 days. With trips every fourth week and feeds every second week, about one feeding day in two falls in a trip, starting next Wednesday. The owner plans to give any feed that falls in a trip on the day back and count the next 14 days from there; a club member suggests granules scattered before each trip instead, or a double can the day before leaving.What should the feeding plan say?
Scatter granules before each trip, since they keep the trees fed while no one is there to mixSkip any feed due in a trip and wait for the next feeding day, since a missed feed is not owedGive each tree a double can the day before leaving, since the extra feed will last the tripFeed on return, once the check allows, and count 14 days from it, since the interval can shift

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