Gardening Tip of the Week
Harvesting and storing Garlic
If you planted garlic last fall right about now is when it should be time to harvest. There may be a difference of a few weeks based on what variety of garlic you planted.
When figuring if it is time to harvest garlic take a look at the leaves. There isn’t a perfect measurement to tell when garlic is finished, but usually when about half the leaves on your garlic plants are brown and dried out, they are close to being ready. If they are at the stage you should stop watering them for about a week before harvesting. This will dry out the garlic and let them store longer. After that week pull all of the garlic, it should be as simple as pulling the plants out of the ground, but if not then use a trowel or something to loosen the soil around the plant, making sure not to nick any of the garlic bulbs. After they are all out brush off the excess dirt but do not wash the garlic after you harvest it. Any extra moisture in the bulb will cause the garlic to rot.
Any garlic that you won’t use right away you will need to “cure”. Curing will dry out and enhance the flavor of the garlic. You will need to put your garlic in a shady, dry place that gets lots of air circulation. There will be a strong garlic smell so it is best to have them outside. At Gateway Greening we tie ours in bunches and hang them under our pavilion. If you can’t hang them, laying them on a table or somewhere that won’t get wet will suffice. Make sure to check on them every couple of days to see if any are rotting and toss those ones out. After the month the leaves will be completely brown and dried and the roots will be stiff. The leaves and stems can be cut back to about ½ inch. Also, make sure to pick out your biggest bulbs to plant for next year!
Blossom End Rot of Tomatoes
Tomatoes are starting to set or soon will be depending on the variety and when you planted them. This is when blossom end rot can set. If it does you will not see it until the tomato is fully formed and starting to ripen.
Blossom end rot is not a fungus, it is a structural deficiency caused by inadequate calcium when the tomato is forming. This structural deficiency may provide an entry point for other diseases but even without a fungus, the bottom will be sunken, water-soaked, and may be black or brown and leathery. Some varieties are more prone to it than others – elongated and pear-shaped sauce tomatoes are the most susceptible.
In some areas, blossom end rot occurs simply because there is not enough calcium in the soil. This isn’t usually the case in St. Louis because our soil’s parent material is limestone, which is composed primarily of calcium carbonate (CaCO3). So, adding calcium, as you might assume, may not fix the problem.
What could be the cause is uneven or excessive soil moisture making the abundant calcium unavailable to the plant. The solution is two-fold.
First, mulch the soil with 2-3 inches of compost or leaf mulch. This evens out and maintains soil moisture as the mercury climbs. It also suppresses weeds and improves soil structure and health.
Second, check soil moisture before watering. Insert your finger 2″ deep into the soil. If it is moist, hold off another day or so. If it is dry or nearly dry, water deeply.
Another potential cause that the plant is growing too vigorously and the plant couldn’t keep up with its calcium uptake. This vigorous growth is caused by excessive nitrogen. If you are fertilizing your tomatoes, make sure that you are using an OMRI-certified fertilizer lower in nitrogen, lower the dose, and/or fertilize it less frequently. However, regular application of healthy compost, crop rotation, and planting cover crops to promote long-term soil health is preferable to regular fertilizing.
Some info on Composting
Composting can seem a bit daunting, particularly if you read a lot about it before you get started. But the best adage about compost is: Compost happens. It is the natural breakdown of organic material.
Short of placing your organic material in a sterile vacuum, it will eventually rot and turn into humus. Composting is managing that decomposition so that it happens as quickly as possibly with few of the… ahem… unpleasant aspects of decomposition (strong oder, pesky flies).
Many people are under the impression that there is only one right way of composting: hot and fast. Composting like this does retain more mass and nutrients and quickly converts the material that is most likely to attract pests. It also provides a steady stream of compost for your garden, a new batch in as little as every 6 weeks*. Hot composting also involves a lot of thermophilic bacteria, which heat up compost piles to 145°F or more, killing off many pathogens and weed seeds.
However, you have to work a bit for all of these benefits. Hot composting needs a good amount of material, requires regular management of the compost pile, and usually involves a workout. To get this process started, you need at least 1 cubic yard (3’x3’x3′) of material that is of a mixture of 3-4 parts browns/carbon and 1 part greens/nitrogen** layered like a cake. It also requires regular turning with a pitchfork to keep the pile well oxygenated and to move materials into the middle where they will also be subjected to the 145°F+ temperatures.
Cold composting means that it will take longer (a year or so) but basically requires little but making sure you have a good balance of greens and browns and that the greens are well-covered. You still get a great, free soil amendment – just somewhat less and a lot slower – and you are still diverting a lot of organic waste from the landfill.
To cold compost, you simply add material as you have it, covering kitchen waste and other green waste with a healthy layer of browns to keep the pests away and the smell down. Since a cold pile doesn’t heat up reliably, you do need to make sure that you are not adding diseased or infested plants or weed seeds. You can help the process along by turning or aerating it every once in a while.
With either method, if your bin/pile starts to smell, is attracting too many pests, or doesn’t seem to be composting, just do some simple troubleshooting. Usually the solution is as simple as turning it, adding some addition browns or greens, or wetting it down.
*Many methods promise much shorter turn around but 6 weeks is a reasonable estimate for an actively managed pile.
**You may come across widely varying ratios, from as little as 1:1 to as great at 30:1. This has to do with ambiguity about what constitutes a part – volume or mass.
The very detailed oriented may find it interesting to build a pile based on the actual mass of carbon (browns) and nitrogen (greens) of every kind of organic material added, and there are many charts that provide this information. This would be where the 25-30:1 ratios come from as all organic material is some mixture of carbon and nitrogen, but mostly carbon.
However, in the community garden, we don’t usually have the time, control, or inclination to manage pile-building that way. Thus, we are looking for a pile that has about 1″ of greens – green plant material, kitchen waste, overripe veggies – to 3-4″ of browns – dried plant material like dried leaves, straw, wood chips, shredded paper or cardboard. The browns tend to contain a lot more air and, if compressed, it would usually end up being similar in volume to the greens, hence the 1:1 ratio.
As the weather warms, we are seeing more evidence of pest activity in our vegetable gardens. One pest that becomes particularly active in June is the cucumber beetle. The adults, often seen flying around solo or hanging out just underneath the surface of leaves, have two distinctive patterns. The spotted one is often mistaken for the more beneficial ladybird beetle. Contribute to The Big Bug Hunt and report your sighting
Another way to spot the cucumber beetle is to find distinctive tears in many different kinds of leaves (not just cucumbers). While torn leaves are unsightly, the pests may also transmit bacterial wilt and other fatal diseases to your crops.
For control options, The Big Bug Hunt and High Mowing Seeds has some good options. Neem oil is another. Or, as many gardeners choose, plant plenty of cucumbers and harvest as much as you can before the beetle damage gets too bad.
Using Coffee Grounds in the Urban Garden
For those of you picking up coffee grounds from the local Starbucks or composting your own, a review of scientific data from Dr. Linda Chalker-Scott at Washington State University provides interesting insights into the commonly held beliefs and hopes of this supposed miracle garden amendment.
First, using grounds as a straight mulch is not recommended, as it can become compacted once wet. Apply in half-inch layers followed by thicker layers of coarse organic mulch.
While the grounds don’t necessarily increase earthworm activity, the worms do pull the grounds into the soil, enhancing drainage and soil structure. pH is widely affected by coffee grounds, and it doesn’t necessarily make the soil more acidic (or less basic). Other amendments (elemental sulfur, peat moss, or pine needles) will work better.
Coffee grounds have been shown to curb some diseases such as Fusarium (a very difficult problem with tomatoes) and Pythium (causing damping off and root rot of seedlings and plants) in beans, cucumbers, spinach, and tomatoes. Using upwards of 20% grounds in a compost pile may show positive results.
For more information, visit: https://puyallup.wsu.edu/wp-content/uploads/sites/403/2015/03/coffee-grounds.pdf
A little about Integrated Pest Management (IPM)
As the weather warms, insect pests can easily wreak havoc on your vegetable garden, regardless of the time you put into protecting it. Dealing with them early will help you manage any potential problems.
One of the most important things to note about pests in the garden is that the presence of a pest species does not necessarily mean you have a pest problem. In a healthy garden environment, beneficial organisms will keep many pest species in check.
The first step before grabbing the spray bottle of unidentifiable liquid, try to identify pests to determine if they are harmful or helpful. Did you know that some wasps actually kill bad pests in your garden? The Missouri Botanical Garden and Texas A&M are good resources for figuring out what insects you have in your garden.
Then, if you’ve determined it is a pest and it is causing damage, we look to the Integrated Pest Management pyramid. First are culture and sanitation, then physical intervention, next biological intervention, and finally chemical intervention. This Top 10 list from Organic Gardening magazine is a great place to start dealing with pests without reaching for a spray or dust.
If you’re seeing pest problems, it is a little late this season to address it with improving soil health, planting plants that attract beneficial insects, and other cultural interventions, though you can plan and possibly plant for later in the season or next year.
However, it is never too late to improve sanitation. Clear away weeds and any plant debris. Many pests are attracted to rotting plant material or are harbored in weedy patches in or near gardens.
Physical interventions can be barriers to prevent pests from getting to the plant or a trap crop that attracts them to a specific area. We use floating row covers on our summer squashes to keep out squash vine borers. When we plant the seeds we immediately put up a floating row cover. We take it off once the plants start to flower to allow for pollination. If you have consistent vine borer problems you can also create collars to prevent squash vine borers from entering the stems. Row covers and insect netting are especially great for cole crops (broccoli, kale, collards, cabbage, etc.) because they don’t require pollination. If you do cover them check on them occasionally to make sure you don’t trap pests under the cover!
The other physical intervention is manual removal. Head out of the garden early in the morning, while most pests are moving slower, locate the pest, pluck it off, and drop it in a bucket of soapy water.
The next level is to introduce biological agents to disrupt the pests. This may be attracting or introducing predators or parasites.
Chemical intervention is the last resort in pest management. For this, think about safe, organic pesticides to rid your plants of the problem pest. But a note of caution, organic is not synonymous with safe. Some organic pesticides are safer than others, so choose with care.
First, select one that targets only the pest you are dealing with. Johnny’s Seeds has a great chart to point you in the right direction. Always follow the instructions and apply the lowest effective dose. But first, consider whether the use of a pesticide is worth it. You may decide it is best to sacrifice the crop, pull it out, and plant something else.
Direct Seeding Warm Season Crops
Do you have space opening up in the garden as you harvest some of those cool-season vegetables? Now is the perfect time to direct seed some warm-season crops to take advantage of that open space.
Beans mature in about 60 days, bush varieties tend to take a bit less, pole varieties a bit more. They do not require anything more than water in a well-prepared garden bed. Pole beans produce over a longer period and do need something to climb – a trellis, teepee, or corn as in the three sister’s garden. Both varieties produce more when they are harvested regularly. Have some fun and plant some purple (though they turn green when cooked) or yellow beans.
The latter half of May and into June is also the perfect time to plant okra. It may grow slowly until it really starts to heat up but when it does, it gets tall, so account for the potential shade it will cast when selecting your spot. Pods appear in about 60 days and should be harvested early – when they are between 2-4″ long. Once the pods get past 4″ they tend to get quite woody and inedible. You can dry and harvest the seeds. Okra can be quite prolific and okra freezes easily – you can put some in the freezer and pull it out for a nice gumbo in the winter – and pickled okra is a favorite!
Finally, most of the cucurbit family – cucumbers, squash, melons – do just fine with planting in late May and into June. Just watch out for the adult squash vine borer in late June. If you’ve had problems in the past, stick to cucumbers, melons, and butternut squash as they are not usually attacked by borers or cover your squash with a floating row cover or insect netting. Keep them covered into they start to flower. You will need to remove the cover to allow for pollination.
If you’re noticing some holes in your cabbages, collards, or other greens it most likely is caused by caterpillars. It always seems right when the plants start looking great that the caterpillars come out in mass. Luckily caterpillars are one of the easy pests to control in the garden.
The best way to get rid of caterpillars is to spray Bt. Bt is short for Bacillus thuringiensis a bacterium that produces a protein when ingested by caterpillars destroys the caterpillar’s stomach. Preventing them from eating and causes them to die. It only affects caterpillars making it very safe to use but also that means if it isn’t caterpillars chewing on your plants it won’t do anything. (There are a few other Bacillus species that target mosquitos, leaf beetles, etc.)
Bt can be found as an Organic Certified spray at most garden stores as well as Gateway Greening. We use every year right around now. You usually will find it in a liquid form (occasionally it is in a powder).
To use Bt you need to follow mixing directions on the bottle. You will need a sprayer of some sort. You can use a large pump sprayer if you have a lot to spray or a spray bottle if you only have a few plants. Spray the leaves directly and make sure to coat the tops and bottoms of the leaves. Bt must be ingested by the caterpillar so you want to make sure all of the leave is coated. It is best practice to spray at least 3 days in a row. Try to avoid spraying before it rains but if it does rain in between just spray again after the plant leaves have dried.
We are now far enough away from our Last-Frost Date (April 15th) to where we can safely plant tomatoes. Even if we have some colder nights coming up it is time to start planting tomatoes. Transplanting tomatoes is different than other seedlings. With other seedlings you plant the seedling at soil level. With tomatoes, you want to plant about half of the seedling below the soil level. Tomatoes will put out roots from the stem wherever it is in contact with soil. Planting it deeply will give the plant a large healthy root system.
After digging a deep hole add fertilizer or compost to the hole before planting the tomato. Make sure to give your tomato plants plenty of space (at least 24” between plants). As they grow you will need to support the tomato plants some way. There are tons of ways to stake and hold-up tomatoes. At Gateway Greening we use a few different methods. Tomato cages to hold individual plants, a weave method to make a wall of tomatoes, and a triangle trellis with string. As the season progresses, we will be showing all three of the methods.
Ways to Extend Lettuce-Growing into Warmer Months
Lettuce is one of the first crops ready to harvest in many spring gardens. It is a great first reward for getting the garden planted early. Though with Missouri’s sometimes short springs lettuce might start to bolt quickly. Bolting is a function of plant stress and cumulative hours of sunlight – so there is a genetic timer that goes off after the lettuce has reached the total number of sunlight hours that induces bolting. You won’t be able to stop lettuce from bolting but you can slow it down. Bolting is the plant going to seed. The lettuce will start to grow a stalk and stretch out and eventually flower. It causes the leaves to become very bitter. Once a plant starts to bolt you can’t stop it. Here are a few ways to extend your lettuce harvests:
First, select varieties that are labeled “slow bolting.” Gardeners frequently complain this claim is overstated but you stand a better chance with these varieties than a variety that has not been bred for that characteristic. Some good varieties are Jericho, Salanova, and Nevada.
Second, keep your lettuce well-watered particularly when the heat sets it. Water every day there is does not rain. Add some leaf mulch or compost around each plant to keep the soil cooler.
Third try to shade the lettuce. Plant summer seedlings on the south and east sides of lettuce. Build trellises and plant beans or other quick climbing crops. If you do not trellis or you didn’t plan for it this season, you can also use shade cloth or lattice propped on something that gives your lettuce enough room.
Remember lettuce will always bolt so once you start seeing some plants bolt the rest will probably bolt pretty soon after.
Fertilizing or adding Compost to Cabbage and Broccoli
If you planted cabbage, broccoli, and cauliflower this spring they will need a little boost from fertilizer or compost. These plants take a while to mature and need to mature before the summer heat arrives. You can add fertilizer or compost depending on what you are wanting to achieve.
If the soil you are growing your cabbage, broccoli, or cauliflower in seems to have lots of nutrients you might only need to add compost. The benefit of adding compost is it will be a slow release of nutrients into the soil as well as insulating the soil and keeping the plants a bit cooler when the summer heat comes. Add about 3 inches of compost onto the soil but make sure to not put the soil right up against the plant. Leave a few inches in diameter circle around the plant compost free. If the compost is right up against the plant it can cause rotting at the base of the plant.
If you are not feeling great about the nutrients in your soil you might want to add a side-dressing of fertilizer. This is typically done about 3 weeks after transplanting. For Cole crops (cabbage, broccoli, cauliflower, kale, etc.) fertilizers high in nitrogen will be the most beneficial.
Citizen Science in the Garden
If you are looking for something to do with your kids or just yourself out in the garden, you may want to think about helping collect data. Gardeners are amateur scientists, observing and experimenting in the garden bed. Why not harness some of that observation for the greater good and participate in some Citizen Science?
The most obvious for the gardener is to participate in The Big Bug Hunt. With this project, you can sign up to receive alerts when pests start to appear in your area so you can take preventative measures to keep pests in check and prevent damage. In turn, you can also report sitings of pests to both help other gardeners and create a fuller picture of what is going on in the pest world.
While there are many others with citizen scientists with topics ranging from aging to zoology, some others relevant to gardeners are Project Bud Burst, a phenology project which tracks the timing of plant changes through the seasons. This is creating a fuller picture of how changes in climate are affecting plant life cycles. The University of Illinois is conducting the The Bee Spotter project, which tracks and identifies bees spotting in Illinois, Missouri, and Iowa. This just requires you to photograph bees you see and submit them to their website.
A similar project that covers all of North America is Bumble Bee Watch, which is documenting the presence of the very important North American bumblebee population (great tomato pollinators!).e-Butterfly is documenting butterfly populations in North American. As with The bee Spotter and Bumble Bee Water, your photograph and submit your photos to their website. If you want to expand beyond pests, pollinators, and plants, iNaturalist, is a program in which you can record and share observations of many different species.
Go forth and collect data!
A Little About Succession Planting
Succession planting works great for root vegetables and lettuces. It is planting every week or so for a month, so you have a consistent harvest instead of all of your plants at once. It is meant only for plants from seeds. For the seeds planted at the end of your succession, it is recommended to look for “heat tolerant” varieties. On top of that, you may want to consider shading the soil. You can either use a shade cloth over hoops or you can use other plants for shading. Okra is a great summer plant that will get to height quickly to shade plants. You can also do a similar technique with different varieties of the same plant that have different Days to Maturity (DTM) if you want to plant them all at once.
As you get ready to transplant seedlings out in your garden beds, remember you might have to harden them off first. The seedlings from Gateway Greening this year have already been hardened. Most garden stores will harden them as well but it is always good to ask. If you started your own seedlings you will need to harden them off. This will involve a 7-10 day process of acclimating seedlings to the outside world, gradually exposing them to more sunlight, cooler temperatures, and less watering.
Start by placing seedlings in partial shade for 3-6 hours and bringing them in at night for the first 3-4 days. Then begin to expose them to more direct sun and cooler temperatures as well as leaving them outside for a few hours more each day. After 7-10 days, they should be out overnight. This process builds cutin in the leaves, a waxy layer that protects the plant from sunscald, dehydration, and disease.
Time to Plant Strawberries
Strawberries are hardy perennials that come back to produce fruit for 3 to 5 years. They can be planted in spring or late fall. Make sure to select a sunny, well-drained site. You can plant them in a raised bed, container, or in the ground as long as there is lots of sun and well-draining soil.
There are three main types of strawberries, June-bearing, Everbearing, and Day-neutral. June-bearing strawberries will produce one big crop of large berries around June. Everbearing will produce a large crop around June and a smaller one in the fall. Day-neutral has smaller berries but can produce berries for a prolonged season in both the spring and fall.
Secure bare-root or container-grown plants. When planting, locate the crown at the center of the plant and bury the roots so that the soil line is just at the base of the crown and the roots are spread out. Any deeper and you risk the crown rotting, too shallow and the plant may dry out. Spacing can vary by variety but it is usually around 12” between plants.
Mulch between all strawberry plants with straw or chopped leaves. This will help to prevent the strawberries from rotting (a common problem when the fruit is in direct contact with the soil) and it will help the soil from drying out. Water thoroughly and keep the bed mulched and weeded through the growing season.
Most strawberry varieties produce runners, which can be trained to take root in a bare batch or, once rooted, transplanted to populate a new bed. However, clipping runners and pinching off early flowers will direct the plants’ growth into their roots, making for a more vigorous plants and better harvests later (but less fruit early in the year). With June-bearing varieties, it is best to pinch off the first season’s flowers. Though difficult, sacrificing the first year’s harvest underwhelming harvest will greatly improve the second year’s harvest.
To harvest strawberries make sure to pinch off the stem versus pulling off the strawberry. Around every other day, pick ALL ripe ones, and any that are diseased or misshapen. In wet or humid weather, cut infected strawberries daily. After picking diseased ones, compost or store separately, and wash hands before picking ripe ones.
Starting Tomatoes Indoors
If you haven’t yet started your tomatoes indoors, now is the perfect time. Tomatoes typically should be started indoors 6-8 weeks before being transplanted, and transplanted about 1-2 weeks after the last frost date for best success.
Keep seedlings warm using a propagation mat (or by putting the planting tray on top of the fridge). Most tomato varieties need about 75⁰ F for best germination rates. Remember that close lighting (1-2 inches) will keep them from getting leggy.
Transfer tomato seedlings into larger pots when they are 2-3 inches tall and have several sets of leaves. At this point, you’ll want to decrease watering to allow some drying to occur between watering. Also, take care to keep the foliage dry to limit the risk of fungus and disease outbreaks.
Onions: Good for More than Just Eating
There is a lot of questionable information and old wives tales circulating about companion planting. Some pairings work well in very specific circumstances and not in others and sometimes the science behind successful pairing is not well-documented. However, one of the tried-and-trues is planting onions among or around your other crops to deter pests – insects and rabbits. The strong scent of onions and all plants from the allium family confuses pests by driving off some pest or by disguising the scent of another crop. Specifically, research has shown they work well at repelling aphids and white flies.
Even if you are not terribly interested in onions as a crop themselves, they are easy to grow interspersed with other crops. And they store well once harvested.
There are a couple of ways to grow onions – they can be started from seed indoors in late winter or direct sown outdoors in early spring. You can sometimes find seedlings to plant as well.
However, the easiest and most common is onion sets, which are young onion bulbs grown from thickly sown seeds (the plants were not given enough room to grow full-size onions). These can be re-planted and with adequate space they will grow into full-size onions. Plant the sets with the point is just level with top of the soil about 4-6 inches apart (or vary depending on what you are planting next to). Like most root crops, onions like a soil that is consistently moist. At Gateway Greening we plant onions in a row border around our Kale, Cabbages, and Collards. This way they don’t take up much space and they provide a border.
We generally use St. Patrick’s Day as our rule of thumb for when to plant potatoes. As with all rules of thumb, it is primarily used for ease of reference rather than its preciseness. There is a wide window of time in which you can plant potatoes in early spring but we associate potatoes with the Irish and so the week of St. Patrick’s Day it is.
However, rather than strictly adhering to the calendar, what you are looking for is friable soil, or soil that is about the texture of a moist cake that crumbles with you work it in your hands. As we’ve had a warmer past couple days, the soil is ready assuming it is not too wet from this past weekend’s rain.
Get certified seed potatoes from a good source (such as Gateway Greening) and cut them into 2-inch chunks that have at least two eyes on each of them. Ideally, you would cut them a day or so before you intend to plant and place the chunks in a single layer, allowing the cuts to “heal” before planting. In addition, before you cut them, you can green sprout them or allow the eyes to develop a more substantial shoot. Neither green sprouting or healing isn’t absolutely necessary but it can reduce the loss to rot, particularly if the soil is wet or cool.
To plant, you dig a trench in your bed and plant chunks about 6” deep in good, friable, well-drained soil. Cover the hole or trench with a little less soil so the seed potato is covered by about 3-4” soil.
As the plants grow, pull soil from around the plant and hill around the base and develop tubers. This will allow better rooting and decrease sun exposure of the potatoes that will want to stick up from the soil. If you run short on soil, amend with compost as you go. Straw also makes an excellent hilling material.
You do want to make sure your potatoes are covered because potatoes exposed to the sun for too long, they develop chlorophyll – turning them green – and solanine. While the green from the chlorophyll is not a problem, it indicates that solanine is present and solanine is toxic to us. If enough is ingested it can lead to an upset stomach. It is rare to eat enough to cause problems because it is bitter but in either case, allowing potatoes to green ruins the crop.
Once the plants bloom, you can steal a few “new” potatoes by carefully reaching into the hills and removing some tubers from the roots. Wait until the plant foliage dies back to dig out mature potatoes.
Get a Jump on Spring Planting with Row Covers, Hoop Beds, and Cold Frames
Small lettuce plants underneath row cover that is being held up by PVC pipes
You can start your cold-weather crops outdoors in the next couple of weeks if you add row covers, hoop beds, or a cold frame to your garden. Covers, hoop beds, and frames are all designed to warm the soil and protect early crops from frost. Don’t rush to put out tender plants just yet, but plan ahead and your cool weather greens will flourish with a little extra warmth and protection.
Adding a hoop cover to an existing raised bed in an easy and inexpensive project. Feed 1/2″ PVC pipe through pipe straps attached every 3-4′ to the outside of a long side of the bed frame. Bend the PVC over the bed and feed it through corresponding straps on the opposite side of the bed.
Lay plastic sheeting (minimum of 3.5 mil thickness) over the PVC frame and weigh down long edges with bricks, stones, or filled water bottles or milk jugs. Alternatively, sandwich the long edges of the sheeting between two pieces of wood and secure the wood to the outside of the bed. This has the added benefit of providing a rigid core to roll the sheeting up to access the bed and for storing over the summer.
Use clamps to gather and close ends for easy access and venting on warm days.