Different seeds need different conditions

Seeds are handled differently based upon their size, whether they require light or darkness to germinate, whether they need special conditions to germinate, such as fluctuating temperatures or measures to make the outside coat permeable, and how long they take to reach maturity once they are successfully germinated.

Some seeds are far more easily directly seeded outdoors once temperatures rise because they reach blooming size in a matter of weeks. We will start with those.

Direct seed nasturtiums

Nasturtiums are easily started by simply pushing the large seeds into the ground. I wait until temperatures are in the 70's, but it really can be done four to six weeks before the last frost date in your zone. As long as temperatures remain above 50 at night, you can feel comfortable planting them. There are two major types of nasturtiums, and it is important that they not be confused! Some merely bunch up and remain essentially compact, while others can reach several feet in length.

We will start with the climbing nasturtiums. If you have a cold winter, you can plant these from April to June. If you have a mild winter, from March to July. They grow in full sun to partial shade, take 9-12 days to germinate, should be planted 3-4 inches apart, and their mature height is 4 to 6 feet. These Nasturtium majus climbed my stairs on their own! They are also great in hanging baskets, and wonderful sprawling over rocks.

Climbing nasturtiums

Then there are clumping, or mounding nasturtiums, sometimes referred to as minus, but they are often termed majus, so just examine the package. Cultural conditions are the same as above, but these are only one foot tall. My personal favorite for bright and vibrant color is 'Mahogany Whirlybird'. The great thing about the 'Whirlybird' types is that the flowers grow above the foliage, but these come in wonderful tones. The other type of clumping nasturtium that has flowers over leaves is called 'Tip Top'. Tip Top is really fun because it comes in colors like Apricot, Salmon, Milkmaid - the latter a very pale yellow - and others. Grow them both. And if you get a mix, you can collect the seeds at the end of the year, dry them, store them in a paper bag, and create your own single colors. The only thing to remember about these wonderful plants is that fertilization results in a great deal of foliage. So no fertilizer should be added at all!

Clumping nasturtiums

Direct seed four o'clocks

Mirabilis jalapa is another seed that can simply be pushed into the ground. It comes in both mixes and in individual colors, such as a pinky lavender. They can grow as tall as four feet - closer to two and a half in my cold climate, and some people actually grow them as hedges.

Pink mirabilis

Truly, you just stick these in the ground and walk away. Do take care if you are in a warmer zone, particularly 7 to 10. These plants actually form tubers (they are often sold that way) and while they tend to die out entirely in my cold zone, just leaving seed, in warm zones they can become quite formidable tubers and will come back every year. And they bloom until a sharp frost takes them out.

Here is is fuchsia, mixing nicely into the beds.

Fusgcia mirabilis

And yellow!

Yellow mirabilis

Do be aware that there is a reason why this plant has several nicknames, and one of them is Four O'Clocks. They do not open until the afternoon (perfect for people who work!) and out of bloom are no more than pleasant, but they are not unattractive before bloom. Here they are in white. And on cloudy days, they stay open for most of the day.

And by the way, there is now an orange version, which I have just ordered for a client who loves orange.

Closed mirabilis in white

Direct seed balsam and verbena

Impatiens balsamina (aka 'Touch Me Not' because the seeds explode on contact) can simply be pressed into the surface of the ground. It comes in blends but by collecting seed you can separate it into individual colors.

Another wonderful plant that is easily started outdoors is Verbena bonariensis. It is so eager a plant that once you have it, you always will. A hit with the Victorians, it actually originated in Argentina. I started a few from seed indoors, and was blown away in following years by its happy seeding. It has a small rootball, so it won't dislodge other plants. When I moved to my new garden I simply threw some seed on the ground and voila. It is wonderful because hummingbirds and butterflies love it, and it has see through stems, so it can be grown in the front, middle and back of the border.

impatiens balsamina

Start nicotiana indoors

Nicotiana alata (also known as jasmine tobacco) can be started indoors, but one year I just threw it outside and it germinated beautifully. So save some effort and just put it outside and press it into the ground. This is another plant that does not open until the evening, and in fact looks a bit droopy during the day. But it is also a plant that has a scent that stopped my neighbors in their tracks when they were out in the evening, because the scent is so wonderful.

One precaution. Nicotiana alata has a rather large rootball, so it is capable of pushing even perennials out of the ground. So do be careful to monitor its creep, and be prepared to yank it out of the ground if it comes to close to a plant that you treasure.

Nicotiana alata

Direct seed Salvia viridis

Salvia viridis, aka Salvia hominum is an heirloom plant that is tender, but can literally be started by pressing seeds into the ground, and it then drops seeds and comes back year after year. Completely non-invasive, with a small root system, it is commonly sold as very inexpensively as seed, and it blooms much earlier in the year than a number of other salvias. The readily available colors are pink, blue, and white, and they make great dried flowers because the color is in the bracts, meaning that they last a long time in the garden.

Here the blue accompanies Lilium auratum.

Salvia viridis in blue

It is also glowing in pink.

Salvia viridis in pink

Start these seeds indoors

Now, which seeds should be started indoors? You can often figure this out pretty quickly, because seeds that need to be started indoors do not return in your garden, at least in my zone.

Ivy geraniums should be started indoors. They are surface seeders but take quite a bit of time to germinate. I start them indoors for better control. I then take cuttings in the fall to reproduce them.

Borage is better started indoors, but does have the virtue of returning reliably and consistently. And it can easily pulled out once it starts to go to seed. This is the white, which is uncommon but readily available. It is typically blue.

Borage in white

Heliotrope should be started indoors. In fact, heliotrope is a plant that I struggle to germinate indoors, because it requires tempertures of about 80% to germinate. I used to start it on top of my refrigerator, because some shop lights were too cool. Is it worth the trouble? Yes! And white heliotrope, which is ravishing and has an almond scent, is unavailable as seed, so you have to buy the plants. In this picture, the tidal wave petunias, the Eragrostis tef and the bit of purple heliotrope were all grown from seed started indoors. But not the white! AARRRG!

Heliotrpe and friends

Petunias should be started indoors. I have started tidal waves, doubles and avalanches indoors. They are all surface seeders so they are easy, but in my zone, petunias do not return on their own. They can, however, be overwintered indoors and then moved back outside.

Salvia farinacea and Salvia cocinea are wonderful plants. While viridis, above, will reseed itself, these tender perennials do not return in my climate. Some of the best are Victoria, Strata (3 colors!) and Snow. Here is a clump of all three that actually survived a zone 5 a winter (ok, only once). They take longer to germinate, so in Zone 5a I start them in February indoors.

Three salvia farinaceas

Beans, in general are started indoors. All of the following are best soaked, preferably until they start to open, and then placed in the ground when temperatures warm. By these I mean hyacinth beans (Dolichos lab lab), and ricinus (do not plant these if children play in your yard, since the seeds, which explode everywhere, are both beautiful and poisonous).

On the other hand, members of the pea or bean family (scarlet runner beans, sweet peas) should be started indoors but put into the ground earlier in the year (March in zone 5a). They grow poorly in warm temperatures, which is why traditional sweet peas perform so much better in the warmer climates of Britain than in the United States. But you will have better luck with Cuthbertson Sweet peas and antique sweet peas, which actually originate in Italy. Try Cupani, Old Spice, or Painted Lady.

Sweet peas

Morning glories can be soaked and then placed in the ground, although (watch out) some of them return in DROVES (Grandpa Otts, I'm calling your name). In my garden, it's actually a nuisance. Cardinal climber, scarlet starglory, and Love- in- a Puff can all be soaked and direct seeded. If you want to test their germination, put them in water for a few days and plant the ones that sprout.

I hope that you will try some of these colorful, long lasting and inexpensive suggestions. Knowing how and when to germinate is half the trick, but it's an easy trick. And it has beautiful results.

Timing is everything with direct sowing. Soil temperature is a crucial factor for when to sow seeds outdoors. The optimal range varies from seed to seed but amongst the vegetables between 60 and 70 F. (15 and 21 C.) seems to be the best. Some plants will germinate at cooler temperatures of 45 to 55 F. (7 and 12 C.). Among these are: Carrots Cabbage Cauliflower Lettuce Peas Radishes Spin

Read more at Gardening Know How: Planting Seeds Outside – Tips On When And How To Direct Sow Seeds https://www.gardeningknowhow.com/garden-how-to/propagation/seeds/how-to-direct-sow-seeds.htm

Timing is everything with direct sowing. Soil temperature is a crucial factor for when to sow seeds outdoors. The optimal range varies from seed to seed but amongst the vegetables between 60 and 70 F. (15 and 21 C.) seems to be the best. Some plants will germinate at cooler temperatures of 45 to 55 F. (7 and 12 C.). Among these are: Carrots Cabbage Cauliflower Lettuce Peas Radishes Spinach

Read more at Gardening Know How: Planting Seeds Outside – Tips On When And How To Direct Sow Seeds https://www.gardeningknowhow.com/garden-how-to/propagation/seeds/how-to-direct-sow-seeds.htm

Timing is everything with direct sowing. Soil temperature is a crucial factor for when to sow seeds outdoors. The optimal range varies from seed to seed but amongst the vegetables between 60 and 70 F. (15 and 21 C.) seems to be the best. Some plants will germinate at cooler temperatures of 45 to 55 F. (7 and 12 C.). Among these are: Carrots Cabbage Cauliflower Lettuce Peas Radishes Spinach

Read more at Gardening Know How: Planting Seeds Outside – Tips On When And How To Direct Sow Seeds https://www.gardeningknowhow.com/garden-how-to/propagation/seeds/how-to-direct-sow-seeds.htm