At the beginning of the year, sow frost-tolerant plants such as spinach, cabbage, lettuce, and broccoli in your unheated greenhouse. These plants endure significantly lower temperatures and are able to be planted outdoors 3-4 weeks before your last frost date.
Yes, Yes, Yes! April is finally here meaning that your garden soil is finally warming up! April is the best time to plant most of your vegetable seeds after your last frost for all zones. It's still not too late to plant tomatoes and peppers from seeds as well!
Crops that are best started indoors include broccoli, brussels sprouts, cabbage, lettuce, and tomatoes. Those with a slower root development, like cauliflower, celery, eggplant, and peppers, should also be started indoors.
Planting in the morning may be best. "In the morning sow thy seed," according to Ecclesiastes, and it is not bad advice for gardeners. Morning planting offers a seed more of what it needs to germinate and fewer dangers.
Starting seedlings off under the protection of a greenhouse, polytunnel or cold frame enables eager gardeners to get a head start on the growing season. Sowing under cover while conditions outside are still less than ideal means you can raise strong, healthy seedlings safe from chilly winds and pests.
The Essentials for Beginners – Greenhouse Gardening 101
- Be seed smart.
- Get a listing of what you'd wish to plant.
- Invest in containers.
- Get sterile soil to prevent plant diseases and pest infestation.
- Add fertilizer to your soil.
- Always water your plants as recommended for each individual plant.
Most seed starter kits contain a tray for collecting water, a tray or cell system for holding seeds, and a clear cover for trapping heat and moisture but letting in light. It's a simple design, but there are many ways to riff on it.
In a cold greenhouse the air temperature inside greenhouse is just a few degrees above the air temperature outside. As long as you can keep the minimum soil temperature for germination, seeds will germinate in a cold greenhouse.
Sheltered from wind, rain and the cold, Greenhouses are the perfect solution for growing your own seedlings! They allow you to control the temperature and humidity, so you can grow seeds at any time of the year.
Yes, seeds normally need to be watered at least once per day to keep the soil moist, not permitting it to dry out. In especially warm climates (or depending on your soil or garden setup), you may need to water more than once per day. Check on your seeds or seedlings frequently to make sure they have plenty of water.
A good aim is to keep the temperature inside the greenhouse between 7 - 21°C (45 - 70°F). The roof vents should provide the majority of the ventilation, with the side vents only being used once the outside air is warmer.
Sow spring cabbage, turnips, Oriental vegetables, chicory, fennel, and autumn/winter salads. Carrots can still be sown, but beware of carrot fly when thinning existing seedlings. Last chance to sow French beans and runner beans (south of England only). Plant out leeks and brassicas for a winter supply, if not yet done.
Vegetables to grow in a greenhouse in winter
- Potatoes. The perfect winter ingredient, you can grow potatoes in either grow sacks or a large bucket/flower pot.
- Winter lettuce.
- Pak choi.
- Spinach and kale.
- Cabbage and broccoli.
- Brussel sprouts.
Besides greens like spinach and lettuce, you can grow cold tolerant veggies such as cabbage and broccoli in your unheated greenhouse. Celery, peas, and the ever popular Brussel sprouts are also excellent cool weather veggie choices for unheated greenhouse growing.
Yes, you can grow vegetables in a greenhouse year-round. Rotate through seasonal vegetables, or set up a dedicated tropical greenhouse.
What can be grown in the greenhouse?
- July is an ideal time to sow spring-flowering perennials in seed trays filled with good quality compost.
- You can also sow summer-flowering perennials such as Scabiosa, Achilea, Echinacea and Geraniums.
Top five veg to sow now
- Onions. I'm not saying that it's easy to grow onions from seed – in fact it's much simpler to plant sets (tiny bulbs) in spring or autumn.
- Microleaves.
- Broad beans.
- Chillies.
- Baby carrots.
- Also worth a try.
- Not worth sowing till much later.
Getting Started: Pick Your Vegetables
| Season | Best Vegetables To Grow |
|---|
| Winter | Brussels sprouts, carrots, cabbage, potatoes, winter squash |
| Spring | Spinach, radishes, broccoli, asparagus |
| Summer | Corn, cucumbers, zucchini, tomatoes |
| Fall | Kale, mushrooms, bell peppers, onions |
In the greenhouse, plant seedlings out when they have two or three leaves. They can be planted into greenhouse borders that have been enriched with plenty of garden compost, 60cm apart, or in growing bags – two plants per bag. You can also grow them in large containers filled with peat-free multi-purpose compost.
