Knowing when and how to plant vegetables or flowers is crucial for optimal growth and harvest. Seasonal gardening techniques such as cloches, grow tunnels, and cold frames can extend your growing window for maximum success.
Early spring can be divided into three distinct “mini-seasons”, depending on your climate’s frost-free date, that allows gardeners to begin sowing perennials and cold-tolerant annual plants in early April or later.
Sow Seeds Indoors
Seed starting (also called indoor seed starting) allows gardeners to extend their growing season by starting crops indoors a few weeks before planting them outdoors. It’s a great way of sowing vegetables and flowers that require longer seasons than your climate allows; you can use greenhouses, high tunnels, caterpillar tunnels or recycled plastic milk jugs as seed starters; alternatively, you can purchase plastic seed trays and cells specifically designed to start seeds indoors. Critical to successful seed starting is creating ideal germination conditions – making sure seedlings are ready for transplanting when the weather warms up outdoors!
Before filling containers with seed starting mix, it’s advisable to pre-wet your starting mix to create evenly moist soil conditions without being too dense or compacted, which could hinder germination. Seed packets usually guide the ideal germination temperature – usually, warm-to-hot temperatures are best. Sowing seeds indoors also allows gardeners to control their environment more effectively by simulating ideal conditions that could speed and ensure more uniform germination rates.
To sow seeds successfully, read and follow the instructions on your seed packet carefully, guiding you on when each crop should be started. For instance, lettuce and other cool-season veggies, such as cucumbers, should be planted early, while hot-weather crops, such as tomatoes and peppers, require planting later.
Starting seeds indoors has many advantages over starting them outdoors; once completed, many supplies can be reused again and again. Seed trays and cells, for instance, can be repurposed year after year to start different crops, from herbs and flowers to vegetables and annuals, as long as they’re labelled with their name and date of sowing.
Mark each container with a popsicle stick or ribbon to quickly identify and transport your seedlings outdoors when the time comes. Before planting them outside, gently prepare their environment by “hardening off”, which means running your fingers over their foliage to simulate light breezes – learn more here!
Grow Tunnels
Grow tunnels offer an inexpensive solution to extend your gardening season while protecting crops from pests and frost damage. These non-permanent structures can be assembled over any planting bed by connecting hoops made from wire, pipe (such as #9 gauge steel or PVC), plastic tubing and clear 2- to 6-mil polyethene or copolymer sheeting, which is readily available at hardware stores, some even feature UV light inhibitors.
A high tunnel, also known as a polytunnel or hoop house, offers temperatures and humidity higher than the outdoor ambient, helping plants remain above the frontline while extending the season for certain vegetables and fruits. Furthermore, these environments may protect cold-hardy crops that have yet to adapt to life outdoors.
Grow tunnels can be ideal for sowing seeds or transplanting seedlings in the fall when soil temperatures remain suitable for rapid development. To ensure successful results, monitoring internal and external temperatures inside a grow tunnel is vital, particularly on days with intense sun or winds when temperatures soar beyond what is acceptable for crops.
Grow tunnels can also provide crops with protection as they develop. This can be especially helpful in protecting leafy greens and tomatoes from overharvesting, extreme winds, or sunlight exposure.
As with greenhouses, tunnels should be cleaned out and their plastic removed before winter’s arrival to manage soil salinity more effectively by allowing rain and snow to wash away salts through the soil without harming future vegetable crops’ roots. Installing a drip irrigation system within your tunnel will also significantly reduce water splash and disease risks. As with greenhouses, conducting a soil test before installing your tunnel can give an idea of any deficiencies or excesses within its soil composition that may need further attention.
Cold Frames
Cold frames are simple bottomless boxes set in the garden to protect plants from frost damage. Home gardeners typically opt for prefabricated cold frames made of timber and plastic; however, you can easily construct your frame using windows, glass or plexiglass (see photo).
Cold frames are ideal for growing cold-season crops like lettuce and radishes, retaining sunlight and warmth for their plants growing inside. To get an early start with salad greens in fall or early spring planting, start seeds indoors two weeks before their anticipated frost date and transplant them directly into a cold frame two weeks before the expected frost date – then open up during daytime hours while protecting from excessive heat or wind damage.
Cold frames extend your planting season and can accelerate cool-season crop growth once they’ve been transplanted outside in your garden. Sowing peas or legumes directly onto cold-frame soil in fall or early spring before covering them with hay or straw to warm the soil can help increase the speed of development once transplanted to garden beds or plots.
Cold frames can help extend your planting window for cool-season crops like peas and beans and leafy vegetables like lettuce. But it’s important to remember that air in a cold frame tends to dry out more quickly than outdoors – keeping the soil damp is critical, while providing additional insulating materials may also help.
Cold frames can be constructed from any available material; corrugated plastic sheeting or old windows work particularly well. If using old windows for this project, be sure to first inspect them for lead-based paint before placing them inside your cold frame.
Repurposing concrete blocks as an economical material solution is another effective way to reduce material costs. Stack them in a rectangle, cover them with clear panels, and position the panels so sunlight passes through during the day before slowly releasing heat overnight and warming your plant beds inside your cold frame. Moveable panels may be moved to block out direct sunlight if necessary before being closed at night to let plants chill down naturally overnight. A thermometer inside your cold frame is essential to monitor temperatures and prevent overheating on hot days, while ventilation helps protect against plant “cooking”.
Cover Crops
Cover crops – plant species designed to support other cropping systems by offering benefits like soil erosion control, carbon sequestration, nitrogen-fixing, weed suppression and more – have become popular with farmers and gardeners. Cover crops can help increase soil organic matter, prevent erosion, improve drainage/infiltration/drainage efficiency, and serve as fodder for livestock grazing. They come in grasses (annual ryegrass, oats, and hairy vetch are three common examples), legumes, and broadleaf non-legumes.
Many small farms and food gardens use various cover crop species depending on the needs of their fields and gardens. Experimentation should be carried out to assess which ones provide the most benefits – each will have unique properties and characteristics which could hamper their ability to do what is intended.
Crimson clover and Austrian winter pea are great cover crop choices for fixing nitrogen, while annual ryegrass can help break up compacted soils. In addition, certain cover crops can even recoup nitrogen left behind from commercial fertilizers by drawing it up through their roots before dispensing it back into the soil.
Cover cropping combined with vegetable production is an efficient way to extend the planting window, control erosion, and improve soil organic matter levels. For optimal results, interest your cover crop immediately following final cultivation of your vegetable field in late August/early September while there is still sufficient moisture available to establish seedlings – this allows an early start on winter cover crop season, which provides erosion control benefits while also increasing soil organic matter content.
As fall draws to a close, now is also an ideal time to plant winter cover crops such as hairy vetch, rye or oats to provide enough nutrients for their growth. Set aside an appropriate time and date when planting it, as cover crops will take some time before giving winter protection.