Cucmber beetle come in July - spray with neem oil and soap as preventative.

You can improve the health of the plant and the yield by pruning. First, determine whether you want one or two main central stems. With two stems, you’ll have more foliage to protect the fruit and you’ll get a large harvest; but if you remove all but one central stem, you’ll harvest your fruit earlier.
Suckers are stems that develop in the crotch between a main stem and a side branch. Pinching out suckers lets more sunlight into the central parts of the plant and allows better air circulation while dense foliage promotes slow growth and disease. Removing all of the suckers reduces the yield, but you’ll probably want to remove some of them to promote healthy growth. gardeningknowhow

Much like their nightshade cousin the tomato, tomatillos sprout roots along the stems and therefore profits from being planted deeply in the garden.
If space is limited, pinch off the growing tips to control spread.
Tomatillos do well with regular application of a fertilizer that is high in phosphorous and potassium. Before planting, amend the soil with a 10-10-10 fertilizer,
After harvesting the first fruits, apply a second feeding consisting of 5-10-10 fertilizer, using 1/2 cup for each plant. This second feeding helps tomatillos continue flowering and producing fruit.
When frost threatens, pull up your tomatillo plants and hang them upside down in an unheated garage. The tomatillo fruits will keep for at least a couple of months.
the more you pick, the more flowers the plant will set.
For green varieties, fruit that is more yellow will be sweeter (but harvest before they turn a pale yellow, as they lose their desired tanginess as they ripen); for purple varieties, fruit should be more purple than green for sweetness. With both varieties, a green fruit means a tart fruit.
Mulching heavily with straw is also a great organic way to control potato beetles because it creates a habitat for predators such as ground beetles, ladybugs, and green lacewings.
You can prevent many of the diseases that affect tomatillos by spacing them properly and growing them up stakes or in cages. Keeping the plants off the ground makes them easier to harvest. It also helps keep the plants dry and allows air to circulate around them.
Although pruning is not necessary, I find it helpful to manage the size of my plant and improve air circulation. To do so, prune tomatillos to one or two vigorous stems by snapping off “suckers” (stems growing from where leaf stems meet the main stem) when they are 2 to 4 inches long. neverthyme

3-4 plants in 16 inch wide container -California Gardening
Tomatillo Planting, Growing, Harvesting
Ontario growing Plant the tomatillo seeds about ¼” deep. For those who live in areas without frost, the seeds can be sown directly into the ground. Northern gardeners should sow seeds into peat pots for later transplantation. The seeds will take a little longer than a week to germinate. Keep the soil moist and protect young seedlings from frost.

Transplanting Tomatillo Seedlings

Once the danger of frost is past, move the tomatillo seedlings outdoors. Transplant the seedlings into rows where the plants are about 2 feet apart. When transplanting tomatillo plants, cut off the bottom few leaves and bury the plant in the ground, leaving only the top few leaves exposed. This will cause the bottom of the plant to produce more roots, which will create a better support system for the young plant as it grows.

Tomatillo plants are quite vigorous and spreading: the plants will quickly “take over” any other plants in the bed, so be sure to provide them with their own place to grow. As tomatillo plants become quite large and sprawling, it is a good idea to use a tomato cage. This helps to keep the tomatillo plants contained and upright, and makes finding the fruit easier in the plants.

Tomatillo Plant Care

Tomatillos require similar growing conditions to tomatoes. They like warm (or hot) weather. Water frequently, and use a fertilizer high in phosphorus and potassium once the plants begin to flower.

Tomatillos are quite resistant to insects and diseases – they are a joy to grow because they are nearly maintenance-free. Some tomatillos will have problems with fungal diseases in areas with high humidity: any fungicide will work to eliminate the problem. Planting the plants with sufficient room for air circulation will help to prevent fungal problems with the plants.

Tomatillo Fruit Development

Many first-time tomatillo gardeners will panic: “My tomatillos have started to grow, but the husks are empty!”

Tomatillos grow by producing the husk first, and then the berry develops inside and gets larger as it matures. Empty husks are not a problem: they are simply the very beginning of the process! After a few weeks, the tomatillo berry will get bigger and bigger. Soon, the husks will be tight around the tomatillo fruit.

When Are Tomatillos Ripe?

Green varieties of tomatillo are ripe when the husk is tight and the fruit begins to split the husk. The husk will turn from green to a muted straw color, and will begin to appear dry. If the fruit remains on the plant, it will eventually turn yellow. The tangy flavor is lost as the fruit becomes over-ripe, so be sure to pick the berries when they are firm, green, and the husk has been split.

Purple varieties are ripe when the fruit splits the husk and the fruit is purple. Some purple varieties need exposure to strong sunlight to develop the full purple color. Note that purple tomatillos become sweeter when fully ripe: if a traditional (tangy) tomatillo flavor is desired, pick the fruit before it turns purple.

Storing Tomatillos

As tomatillos are indeterminate, it can take a week or two to obtain enough fruit to make a sauce or salsa. Tomatillos store very well, as long as the husk is kept in place. Simply pull the fruit off the plant, leave the husk in place, and store on the counter for a week or two. Once enough fruit is gathered, make a tomatillo salsa or can the tomatillos for future use. Discard any fruit that appears soft or wrinkled. -dengarden

2) Plant seeds. Plant seeds 1/4" deep in the soil. Cover with soil and water carefully. Over watering can cause fungal growth which leads to seed rot. Excess water can also bury seeds deep in the soil where they will not be able break the surface. Water when the soil surface just begins to dry. Multiple seeds can be planted in a single starter container, but should be thinned once seedlings appear so only a single plant remains.

3) Germination. Soil should be kept consistently warm, from 70-85F. Cool soils, below about 60-65F, even just at night, will significantly delay or inhibit germination. Hot soils above 95F will also inhibit germination.

4) Care of seedlings. Once a few true leaves have developed, seedlings should be slowly moved outside (if sprouted indoors) to ambient light. Care should be taken not to expose seedlings to direct, scorching sun so plants may need to be hardened off via slow sun exposure. Hardening off can be done using a shaded or filtered light location, as well as protection from strong winds, rain or low humidity. Hardening off time varies, but can take 5-10 days.

5) Planting out. Plant in the ground once danger of frost has past and daytime temperatures consistently reach 65F. tradewindsfruit Start tomatillos indoors 8 to 6 weeks before the average last frost date. Transplant seedlings into the garden two weeks after the last frost just as you would peppers and tomatoes.

Tomatillos can be grown much like tomatoes, but they are more sensitive to cold and chilly temperatures much like peppers. Protect tomatillos from night time temperatures cooler than 55°F (13°C).

Tomatillos mature 60 to 80 days after transplanting. Seedlings for transplanting should be about 40 to 50 days old at transplanting time. That means tomatillos from sowing require 100 to 130 days to reach maturity depending on the variety.

Transfer seedlings to a larger container once they are 2 to 4 inches (5-10 cm) tall; be sure that seedlings have sufficient room for root growth. This process is called “potting up”; continue to pot up seedlings as they outgrow containers—until they are transplanted into the garden or a very large container. Transplant tomatillos once they are 4 to 6 inches (10-15 cm) tall; transplant into medium-rich garden soil 24 inches (60 cm) apart in rows at least 24 inches apart.

Grow tomatillos in full sun for best yield. If you transplant seedlings started by another grower, select plants 6 to 8 weeks old; usually in a 4-inch (10 cm) pot. Check the bottom of the pot to be sure roots are not growing through and the plant is not root bound.
Interplanting: Plant tomatillos with bush beans, chives, cucumbers, lettuce, marigolds, eggplant, tomatoes.
Container Growing: Choose a 10-gallon container or larger.
Recommended varieties: ‘DeMilpa’ is an heirloom; ‘Purple’ has deep purple skin; ‘Toma Verde’ is early to harvest.
Botanical Name: Physalis ixocarpa
harvesttotable