All plants

Summer Squash

Cucurbita pepo

Cucurbitaceae · gourd family

Matures
50–60 days
Harvest
Continuous · Annual
Sun
6–8+ hrs
Spacing
24–48 in
Botanical engraving of Summer Squash

Planting window

When to sow, by microclimate — foggier blocks run a different calendar than sunnier ones.

JanFebMarAprMayJun
Foggy◐◐●●
Sunny◐●●●
JulAugSepOctNovDec
Foggy◐◐
Sunny◐◐
Well-suitedMarginalNot suited

Sunlight

How well it does at each level of direct sun per day.

<2 hrsNot suited
2–4 hrsNot suited
4–6 hrsMarginal
6–8 hrsWell-suited
8+ hrsWell-suited
Well-suitedMarginalNot suited

Soil depth

Root room it needs — useful for sizing raised beds and containers.

6–10"Not suited
10–15"Not suited
15–18"Marginal
18–24"Well-suited
Well-suitedMarginalNot suited

Spacing

Room each plant needs — along the row and between rows — for sizing beds.

In-row
24–48 in
Between rows
48 in

Growth habit

The shape it makes in the bed and how tall it gets — what tells you whether to give it a trellis, a stake, or just room.

Habit
Upright
Mature height
1–2.5 ft

Stands on its own; the tallest types appreciate a stake in wind.

How to start it

Sow it where it grows, or raise it under cover and set it out — and how far ahead to start the seedlings if it's the latter.

Usually
Direct-sow
Start indoors
4 weeks ahead
Direct-sowWell-suited
TransplantWell-suited

Sown straight into the bed it will grow in.

Well-suitedMarginalNot suited

Getting started

How it goes in the ground — how deep to sow or set it, and the soil temperature it needs to wake up. The cold-soil floor is the real limiter for direct-sowing in a foggy SF spring.

Started from
From seed
Ideal soil temp
85–95°F
Sow depth
1–1.5 in
Time to emerge
5–10 days

Germinates between 60–105°F; happiest around 85–95°F.

30°F110°F
IdealWorkable

Pests & diseases

What tends to trouble this crop — what it is, what you'll see, and what to do about it, least-toxic first.

Pests14

Aphids
What it is
Aphids have soft pear-shaped bodies with long legs and antennae and may be green, yellow, brown, red, or black depending on the species and the plants they feed on. A few species appear waxy or woolly due to the secretion of a waxy white or gray substance over their body surface.
What you'll see
Low to moderate numbers of leaf-feeding aphids aren't usually damaging in gardens or on trees. However, large populations can turn leaves yellow and stunt shoots; aphids can also produce large quantities of a sticky exudate known as honeydew, which often turns black with the growth of a sooty mold fungus.
What to do
Before planting vegetables, check surrounding areas for sources of aphids and remove these sources. On the other hand, these aphid-infested weeds can sometimes provide an early source of aphid natural enemies.
Source
Armyworms
What it is
Armyworm larvae feed in groups, which distinguishes them from other vegetable pests such as corn earworms and loopers. Markings on newly hatched armyworms are usually hard to distinguish from those of other caterpillars; older larvae have distinct lengthwise stripes.
What you'll see
Armyworms may feed on the crowns of seedlings. On larger plants, armyworm caterpillars skeletonize leaves.
What to do
Handpick. Virus diseases, parasites (Hyposoter and Trichogramma), and general predators may be effective on caterpillars.
Source
Cucumber Beetles
What it is
Adult beetles are shiny with black heads, long antennae, and about 1/4 inch long. Adults may be striped or spotted, depending upon species.
What you'll see
Adults feed on the leaves of many vegetables as well as on soft fruit. Shoots and blossoms may also be consumed.
What to do
Management of cucumber beetles is difficult. The best strategy for most vegetable gardens may be to place protective cloth over emerging plants and remove it when plants are old enough to tolerate damage.
Source
Cutworms
What it is
Cutworms are dull brown caterpillars ranging in length from 1 to 2 inches when fully grown. They curl into a C-shape when disturbed.
What you'll see
Cutworms feed on blossoms and leaves of many ornamental plants and attack most garden crops. They clip off seedling stems near or just below the soil level.
What to do
Cutworms are pests mainly in the spring. Destroy crop residues; keep garden weed-free in winter.
Source
Earwigs
What it is
The adult earwig is readily identified by a pair of prominent appendages that resemble forceps at the tail end of its body. Used for defense, the forceps are somewhat curved in the male but straighter in the female.
What you'll see
European earwigs feed on a variety of dead and living organisms, including insects, mites, and growing shoots of plants. They are voracious feeders on soft-bodied insects such as aphids and insect eggs and can exert significant biological control under some circumstances.
What to do
Management of earwigs requires an integrated program that takes advantage of their habitat preferences. Initiate a regular trapping program.
Source
Flea Beetles
What it is
Their small size, enlarged back legs, characteristic shot-hole damage, and habit of jumping when disturbed make flea beetles easy to identify. There are numerous flea beetle species.
What you'll see
Adults feed mostly on leaves, leaving tiny pits or small holes at their feeding sites. Flea beetles feeding together can cover leaves with bleached, pitted areas or ragged holes.
What to do
Remove debris in the fall to remove any overwintering beetles. Reflective mulches applied very soon after planting and before plants become infected can be helpful.
Source
Leafhoppers
What it is
Leaf stippling (bleached specks) is commonly the most obvious indication that leafhoppers or certain other arthropods that suck plant juices are present. Because discolored spots or overall bleaching of leaves are also caused by lace bugs, plant bugs and other true bugs, spider mites, and thrips, examine the underside of leaves for the arthropods themselves to distinguish the cause of damage.
What you'll see
Leafhopper feeding causes leaves to develop pale specks (stippling). Leaves and shoot tips fed upon by an abundance of leafhoppers may turn yellow then brown and curl and die.
What to do
In most situations, leafhoppers are just an annoyance or curiosity and do not threaten plant survival. Leafhoppers have many natural enemies, including assassin bugs, brown lacewings, damsel bugs, green lacewings, lady beetles, minute pirate bugs, and spiders.
Source
Loopers
What it is
Loopers are green caterpillars with several white stripes down their backs. They arch their backs as they crawl, this looping movement giving them their name.
What you'll see
Loopers eat irregular holes in leaves, most often older leaves. They may also bore holes in lettuce and cabbage heads or damage fruit.
What to do
Handpick. Apply Bacillus thuringiensis or spinosad; they are effective against loopers, especially when caterpillars are small.
Source
Snails and Slugs
What you'll see
Snails and slugs feed on a variety of living plants and on decaying plant matter. They create irregular holes with smooth edges on leaves and flowers by scraping with their rasp-like tongues.
What to do
It will not be possible to eliminate some shelters, such as low ledges on fences, the undersides of wooden decks, and water meter boxes, so make a regular practice of trapping and removing snails and slugs from these areas. The survivors congregate in the remaining shelters, where you can more easily locate and remove them.
Source
Spider Mites
What it is
To the naked eye, spider mites look like tiny, moving dots; however, you can see them easily with a 10X hand lens. Adult females, the largest forms, are less than 1/20 inch long.
What you'll see
Mites cause damage by sucking cell contents from leaves. A small number of mites usually isn’t reason for concern, but very high populations—levels high enough to show visible damage to leaves—can damage plants, especially herbaceous ones.
What to do
Cultural practices can have a significant impact on spider mites. Mid­season washing of trees and vines with water to remove dust may help prevent serious late-season mite infestations.
Source
Stink Bugs
What it is
Adult stink bugs are distinguished from other insects by the large triangle shape with a rounded rear end (scutellum) that occurs on top of the back, covering the rear of the thorax and front portion of the abdomen. In comparison with most insects, adults are wider relative to their length.
What you'll see
Adults suck and feed on plants with their strawlike mouthparts. Stink bugs attack a variety of fruits, nuts, and vegetables from beans to tomatoes and apples to stone fruits.
What to do
Handpick the bugs and their eggs from small plants. Parasites and general predators can contribute to the control of some stink bug species if natural enemies are not destroyed, such as by the application of persistent, broad-spectrum insecticides.
Source
Thrips
What it is
Most adult thrips are elongate, slender, minute (less than 1/20 inch long), and have long fringes on the margins of both pairs of their long, narrow wings. Immatures (called larvae or nymphs) are oblong or slender and elongate and lack wings.
What you'll see
Thrips feeding on plants can damage fruit, leaves, and shoots and very noticeably affect plants’ cosmetic appearance. However, thrips rarely kill or threaten the survival of trees and shrubs.
What to do
Thrips species that feed on many different plant species often move into gardens and landscapes when plants in weedy areas or grasslands begin to dry in spring or summer. Avoid planting susceptible plants next to these areas, and control nearby weeds that are alternate hosts of pest thrips.
Source
Vegetable Leafminers
What it is
Adult leafminers are small, active, black flies often with a prominent yellow triangle between the bases of the wings. The head behind the eyes is mostly black.
What you'll see
Leafminers attack many different vegetable and flower hosts, including cole crops, cucurbits, tomatoes, peas, beans, aster, begonia, dahlia, impatiens, lily, marigold, petunia, and verbena. Adult female leafminers puncture leaves and sometimes petals to feed on exuding sap.
What to do
Leafminers rarely require treatment in gardens. Clip off and remove older infested leaves.
Source
Whiteflies
What you'll see
Whiteflies use their piercing, needlelike mouthparts to suck sap from phloem, the food-conducting tissues in plant stems and leaves. Large populations can cause leaves to turn yellow, appear dry, or fall off plants.
What to do
Whiteflies have many natural enemies, and outbreaks frequently occur when these natural enemies have been disturbed or destroyed by pesticides, dust buildup, or other factors. General predators include lacewings, bigeyed bugs, and minute pirate bugs.
Source

Diseases5

Cucurbit Viruses
What you'll see
Potyviruses, Mosaic viruses, Cucumber aphidborne yellows, and Lettuce infectious yellows Symptoms of virus diseases include mottling of light green, yellow, or white areas on leaves, clearing of veins, thickening of leaves, and reduction in growth and yield. Fruit may be deformed.
What to do
Viruses are transmitted by insects, such as aphids, whiteflies, and cucumber beetles. Remove infected plants as soon as they are detected.
Source
Downy Mildew on Cucurbits
What it is
Downy mildew growth may initially be confused with powdery mildew. However, the two diseases differ in several important ways.
What you'll see
Downy mildew attacks all cucurbits, although cucumber is the most commonly infected. It appears first as small, pale green to yellow, angular spots delimited by leaf veins that give the foliage a mottled appearance.
What to do
Spores of the downy mildew fungus are carried by air currents or by rain-splash or sprinklers. Avoid using overhead sprinklers.
Source
Powdery Mildew on Cucurbits
What you'll see
Two species of fungi can cause powdery mildew on cucurbits: Sphaerotheca fuliginea and Erysiphe cichoracearum. S. fuliginea is the more common.
What to do
Control weeds and follow good sanitation practices. Avoid overhead sprinklers.
Source
Root Rot on Cucurbits
What you'll see
Phytophthora spp. Root rot can occur on all cucurbits. Crown leaves turn yellow followed by a rapid collapse or wilt of the entire plant.
What to do
Root rot is usually more common on crops planted for a fall harvest and generally follows a period of cool or damp conditions. Plant in high, well-drained beds and avoid heavy clay soils.
Source
Verticillium Wilt on Cucurbits
What you'll see
Verticillium wilt can affect all cucurbits. The first symptoms are wilting and yellowing of crown leaves, which eventually dry up.
What to do
Avoid planting where potatoes, peppers, eggplants, tomatoes, or cucurbits have previously been planted. Some resistant varieties are available.
Source

Disorders1

Blossom End Rot
What you'll see
Blossom end rot affects tomatoes, peppers, and cucurbits. Plants with blossom end rot show small, light brown spots at the blossom end of immature fruit.
What to do
Blossom end rot results from a low level of calcium in the fruit and water balance in the plant. It is aggravated by high soil salt content or low soil moisture and is more common on sandier soils.
Source

Sources

Every figure above is backed by these.