Annual Plants

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Annual Plants (1)

Annual plants prefer soil with a pH between 6.3 and 6.7. The required sunlight, best planting time, and spacing differ for different annual plants. Granular fertilizers and water-soluble/liquid fertilizers are two types of fertilizer used in growing annual plants.

Planting Instructions

  • There are two seasons for planting annual plants in areas that witness severe cold weather with freezing temperatures; cool season and warm season.
  • Flowers such as "begonia, geranium, impatiens, million bells, petunia, and salvia" are some warm-season annual plants that can be planted during spring and summer, while pansies and violas are some cool-season annual flowers.
  • Generally, annuals prefer "well-drained soil with a pH between 6.3 and 6.7."
  • The required spacing and planting time for annual plants vary based on types. The recommended spacing and planting time for some popular annual plants can be found here.


  • The required sunlight for annual plants is dependent on the type of annual plant before selecting an annual plant.
  • Annual plants for full sun can take "8 hours or more of direct, daily sunlight. Part sun plants can take 4 to 6 hours, while plants for shade need 4 hours or less."
  • The required sunlight exposure for annual plants varies based on types. The exposure for some popular annual plants can be found here.


  • The frequency of watering annual plants is dependent on the weather and season. During the rainy season, annual plants would not need watering after a good soaking rain and not a sudden shower.
  • "Drought-tolerant annuals, such as zinnia, marigolds, and cleome, will require minimal watering; once a week will probably be fine. Others, such as snapdragons, alyssum, and impatiens, need regular water or they will suffer stress."
  • To ensure that the watering is sufficient, a minimum soil depth of 2 to 3 inches should be wet.
  • In general, annual plants are to be watered frequently at germination and seedling stage, and once every 10-14 days during dry weather.
  • The watering of annual plants is best done on the base of the plant to ensure that the foliage is dry. When using sprinklers, watering should be done in the morning to ensure that the water on the foliage would dry before the temperature drops.
  • Generally, the best indicator for the watering frequency of annual plants is the plant itself. If the leaves start to wilt, become pale or dull, it's an indication that it needs to be watered. However, avoid over-watering as it also makes the leaves to wilt or become pale.


  • Pruning is dependent on the type of annual plant. Some varieties produce few to no seeds, hence, they would not require pruning "since plants stop blooming when they go to set seed."
  • Annual plants are pruned by using a pruner or scissors to clip-off "as much as one-third of the length of the stems to get them all to be the same length or just trim back the longer ones to come back into line with the rest."


  • Fertilizing annual plants is vital to "encourage growth, and create healthy, vigorous, attractive plants that will produce an abundance of flowers", however, there is also a temptation to over-fertilize.
  • Over-fertilizing an annual plant forces it to grow above its natural growth rate, hence, exposing the plant to insect or disease infestation.
  • It also results in excess foliage with no bloom and reduces the tolerance of the plant to drought or extreme temperatures.
  • Also, fertilizers with high nitrogen content are to be avoided, while more phosphorus is encouraged.
  • Two types of fertilizers used in planting annual plants are granular fertilizers and water-soluble/liquid fertilizers.
  • While granular fertilizers are used at the time of planting and last for the entire season, water-soluble/liquid fertilizers are applied every week or two.

Research Strategy

To provide an overview of the planting instructions, sunlight, watering, and pruning aspects of annual plants, your research team have aggregated sources on the growing of annual plants. Note that we have included sources that are beyond Wonder standard of 24 months maximum. This is because such sources still hold relevance to this research.
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Annual Plants (2)

Fertilizing annuals should be a process that is continued all season and light frost can be combated with a polyspon garden fabric cover. Some pests that commonly affect plants include aphids, flea beetles, slugs, thrips, and others. Common plant diseases that specifically affect annuals are powdery mildew, black spot, gray mold, and white mold. Additional details are below.

Fertilizing Annual Plants

  • The key to annual plant performance is to fertilize them during planting and continue fertilizing them all season long.
  • Fertilizing annual plants when planting them helps them get established. After planting them, annuals should be fertilized monthly through September.
  • Phosphorus is an important part of fertilization as it is "associated with root development;" however, nitrogen is actually more important because it is responsible for green shoot development.
  • When looking at a fertilization product, there will be a set of three numbers, the first of which is for nitrogen, the second of which is for phosphorus, and the third of which is for potassium. If the second number (for phosphorus) is larger than the first one (for nitrogen), do not purchase that product.
  • For example, a 10-10-10 fertilizing product will contain 10% of each nutrient (nitrogen, phosphorus, and potassium).
  • Chemical fertilizers that combine inorganic chemicals to create ammonium nitrate or magnesium sulfate are "inexpensive, readily available, and rapid-growing plants like annual flowers take up the nutrients quickly."

Freeze Care

  • Since annuals have to be replanted every year, they will not survive winter; however, their live can be extended by "keeping polyspun garden fabric handy to cover them during light frosts."
  • Additionally, annual plants should continue to be watered until the frost finally kills them.
  • Watering annuals in the morning is best so that the soil has all day to soak up the water before temperatures drop in the evening.
  • Annuals that are planted in containers will live longer if the containers are moved to a protected space like a shed or a garage whenever the outdoor nighttime temperature drops below 40°F. Moving them to such a space will work until the daytime temperatures also drop to 40°F or below.
  • Frost tolerant annuals like stock, alyssum, pansies, violas, ranunculus bacopa, creeping Jenny, snapdragons, and calibrachoa can help extend the life of annuals beyond the initials light frosts.


  • Aphids affect both indoor and outdoor plants, including annuals and will cause "flowers to wilt and drop" and the foliage to twist or curl. Aphids can be found in all 50 states. Products such as "Doktor Doom House and Garden, End All, [and] Ambush" will help control aphids.
  • Flea beetles affect perennials and annuals and will leave numerous pinhead holes in the foliage. Flea beetles have a "worldwide distribution" and more than 72 species have been found in "America north of Mexico alone." Product such as "Ambush, Dr. Doom House and Garden" will help control flea beetles.
  • Slugs will chew large holes in foliage and leave slime trails on leaves on both perennials and annuals. Since slugs prefer warm, moist, and humid climates, "the Pacific and Atlantic coastal areas are prime regions for slugs... with the Pacific Northwest, tropical and subtropical Hawaii, and Florida especially hard hit." Metaldehyde based pellets help control slug infestations.
  • Spider mites can infest both indoor and outdoor plants and will leave tiny dots and a yellow haze on foliage. Spider mites appear in the Northern and Central states, but are not common in the Southern states or extreme Western states. Products such as "End All, Doktor Doom House and Garden, Ambush" will help control spider mites.
  • Spittlebugs target perennials and annuals and leave "spit" on the plants. Spittlebugs appear in most of the Continental United States. There are no chemical control products that are necessary to control spittlebugs as they can be controlled with jets of water.
  • Stink bugs can affect perennials, annuals, trees, and shrubs, and they will emit a foul-smelling odor when disturbed. Stink bugs have been found in 44 states and four Canadian provinces, but are a severe problem in Michigan, New York, Pennsylvania, New Jersey, Delaware, Maryland, West Virginia, Virginia, North Carolina, and Tennessee. They have not been found in Louisiana, Oklahoma, South Dakota, Wyoming, Montana, or Alaska. Stink bugs typically do not cause enough damage to warrant the use of insecticides.
  • Thrips can affect both indoor and outdoor plants and leave "white blotches or streaks on foliage/blooms." Thrips are common in tropical climates, including those in the United States. Products such as "End All, Doktor Doom House and Garden, Ambush" can help control thrips.



From Part 02