Stark Bro's Plant Manual for American Cranberry

Getting Started


Plants grown in a greenhouse must be acclimated carefully before planting or placing them outdoors. This is especially true in hot or sunny locations. Many species should never be grown in full sun. Before purchasing a plant, learn about its sun requirements. Knowing the plants requirements can avoid any damage to the plant by incorrectly giving it the wrong conditions.

If your plant has been grown in a greenhouse, here are a few steps we recommend you follow:

  • After purchasing your plant, place it outside in a sheltered, shady spot or on your back porch.
  • Leave it there for 3-4 hours and gradually increase the time spent outside by 1-2 hours per day.
  • Bring the plants back indoors each night.
  • Water it regularly to keep the plant moist.
  • Occasionally spray the leaves with water.
  • After 2-3 days, move the plants from their shady spot into morning sun, returning them to the shade in the afternoon.
  • After 7 days, the plants should be able to handle the outdoor temperatures, if they stay around 50 degress F.
  • After 7-10 days, your plant is ready to be planted in its permanent location. Try to do this on a cloudy day and be sure to water the plant well.
  • Observe foliage daily. If any type of leaf discoloration occurs, put the plant back into filtered light and attempt this step at a later date.
  • Special care must be taken to avoid burning the leaves.

These are general guide recommendations. Some plants take longer than others to acclimate.


Few things are as delicious as homegrown cranberries, and the success of your harvest begins right with the planting site and method. For maximum growth and yields later on, give your plants the best foundation possible.

Before Planting

Before you plant, check your soil pH. This can be done by contacting your local County Extension Office for information about soil testing in your area, or purchase one of our digital meters for quick and accurate results. Ideally, your cranberries need a soil pH between 4.5-5.5. To increase the acidity of your soil, use a soil acidifier. Steer clear of soils that are extremely heavy or very poorly drained.

Location and Spacing

  • Pick a location with full sun, good drainage and very fertile soil. Cranberries have a shallow root system that only grows in the top six inches or so.
  • Space your cranberry plants 2' to 3' apart. They will only grow about 8-10 inches high.
  • Amend the soil with organic matter such as dehydrated cow manure, garden compost, peat moss or our Coco-Fiber Potting Medium.

Planting Tips

  • Don’t plant too deep. The crown should be right at the soil level, with the roots just under the surface.
  • If your cranberries are bare root, plant them at same depth as they were grown in the nursery row.
  • If your berries are potted, plant them at the same depth as they were in the pot.
  • Give your new plant a soaking with a solution of Stark® Tre-Pep® Fertilizer. Soil should stay moist without being soaked. (If planting in the fall, wait to fertilize until spring for best results.)

Additional Notes

  • Cranberries ripen over several weeks, so plan to pick more than once.
  • Protect your crop from birds with a Garden Net.
  • Cranberries benefit from a layer of sand every few years.
  • No pruning is necessary at planting time.

Care & Maintenance


Cranberries and lingonberries require little fertilizer. In early spring, use a small handful of fertilizer (such as 5-10-10) and apply in a circle around each mature plant. Use smaller amounts for plants up to three years old. Stop fertilizing by late June.

Insects and Diseases

Every plant has the future potential for disease and insect damage. Factors such as location and weather will play a part in which issues your plants encounters. If available, disease-resistant varieties are the best option for easy care; and for all types of plants, proper maintenance (such as watering, pruning, spraying, weeding, and cleanup) can help keep most insects and diseases at bay.


They are the size of a pin head and vary in color depending on the species. Clusters on stems and under leaves, sucking plant juices. Leaves then curl, thicken, yellow and die. Produce large amounts of a liquid waste called “honeydew”. Aphid sticky residue becomes a growth media for sooty mold.

Natural Control

  • Sometimes you can knock them off with a strong stream of water from your garden hose.

Other Control Options

  • Consult County Extension Agent

White Fly

Adults are tiny, white winged insects found mainly on the underside of leaves. Nymph emerge as white, flat, oval shapes. Larvae are the size of a pinhead. Suck plant juices from leaves causing them to turn yellow, appear to dry or fall off plants.

Natural Control

  • Traps

Other Control Options

  • Consult County Extension Agent


Adults are 1/4” long, flat, oval shaped with a white waxy covering. Yellow to orange eggs are laid within an egg sac. Crawlers are yellow to brown in color. Over winters as an egg or very immature young in or near a white, cottony egg sac, under loose bark or in branch crotches, mostly found on north side. Damage is by contamination of fruit clusters with egg sacs, larvae, adults and honeydew, which promotes growth of black sooty mold.


  • Consult County Extension Agent

Botrytis Blossom Blight

Usually begins on plant debris, weak or inactive plant tissue than invades healthy plant tissue cause spotting and decay of flowers and foliage and fruits or berries.

Natural Control

  • Fall cleanup is essential.

Other Control Options

  • Consult County Extension Agent

Bacterial Leaf Spot

First appears as small dark green, translucent spots that later enlarge and turn black. Usually scattered over the entire surface of the leaf.

Natural Control

  • Serenade® Garden Disease Control


Adult is yellow to brown sawfly beetle, 1/4” long. Larvae are brown and white, 1/8” long. Adults make slits in flower buds and larvae feed on berries.

+Control +

  • Consult County Extension Agent


Newly hatched worms are white with black heads. Mature worms are light tan or dark brown with dark or orange back and side stripes. They feed on the leaves of plants.


  • Consult County Extension Agent


Pruning is an important part of proper edible plant care, and in the case of cranberries, it’s particularly easy to do.

Pruning Tips

  • After the plant begins bearing regularly, usually in the third year, rake lightly in spring just before growth begins.
  • Lift and cut long runners— this will encourage uprights to form. Only prune long runners, not uprights.
  • Remove any dead or damaged growth.


Spraying is important to the survival of your plants. To handle potential diseases and pests, reference the guidelines below to know what you should spray, and when you should use it.

Before you begin, read and follow all instructions on labels.

Natural Control

When To Spray

At the First Sign of:

  • Serenade® Garden Disease Control for leaf spot.


Cranberries and lingonberries require an average amount of water. If you receive about an inch of rainfall every 10 days or so, your plants will be fine. If you have a really dry growing season, give your new plants a good, thorough soaking with a hose.


Are you ready to enjoy delicious homegrown fruit? Harvest is the time to enjoy the results of your hard work. Keep a few things in consideration as you reap the fruits of your labor: the best time to pick the fruit from your tree, and how to store the fruit.

When to Harvest

Your plant should start producing cranberries in 2 to 3 years. Harvest in late September to early October. They develop in large clusters making them easy to pick. When they are ready to harvest the seed turns a brownish color and the berries turn a burgundy color.

When using the berries for sauce, jelly or juice pick them slightly under-ripe. However, if you are going to eat the berries fresh then plan on picking after a frost so the berries will be soft and sweet.

The annual average yield per plant is 3 pounds.


The berries can be kept in the refrigerator for a short time, and may be frozen for later uses. Make sure to wash and stem the berries before freezing.