Seed flats in the greenhouse in early spring. See the large lettuces growing in the beds, between flats of seedlings balanced on the bed walls.
Photo Kathryn Simmons

Preparing for Spring Transplants

We have winter to enjoy/experience/endure before we start spring seedlings, but there are some steps you can take to make spring start-up easier and more successful. Of course, there is the usual list of tidying your workspace, preparing to order seeds and repairing tools.

Replacement tool handles

House Handle Company Telephone: (800) 260-6455 has a wide selection of good quality wood handles online. They specialize in hickory, white oak and ash. Be careful making your selection, and get the handle that’s just right for the tool you are repairing. You can see a lot of their handles in our photos. During the winter we usually have a “Santa’s workshop” day when we repair tools.

There are YouTube videos showing how to make sturdy repairs. Just be sure to shape the handle for a good fit before drilling any holes for rivets. And learn how to make rivets from large nails if none are supplied with your replacement handle. Sharp edges on poking-out badly finished rivets, or nuts and bolts can cause injuries. Sweat we might need. Blood and tears we can do without.

Screening a large pile of compost for the greenhouse beds. Photo Wren Vile

Seed Compost

Today I’m thinking about seed and potting compost.

We use 100% home-made compost for sowing seeds, and for potting-up transplants. We don’t mix in any other ingredients. Our seed compost is our regular good-quality compost, screened to remove large particles, and matured over the winter into a very mellow combination of nutrients and micro-organisms. We make great compost and it grows big strong plants.

We screen a big pile of compost in September, and fill the cinder-block beds in our solar-heated greenhouse. See this post: Screening compost to make our own seed compost for spring. If you are making your own screens, you can use hardware cloth (rat-wire), or do as reader Jim Poole suggested and try stucco lathing instead. “It is quite a bit sturdier. (But watch out for the cut ends when installing it- it can give you a nasty gash.)”

We need a lot of compost, but the idea works fine on a smaller scale too. Find an indoor place near where you will use the compost in the spring, and some tubs to put the screened compost into. If you want the full tub to be on a bench in spring, put the empty one on the bench and screen into it! If you want to grow lettuces in the compost, put the tubs near a window.

Just storing the compost inside over the winter will mean you are not dealing with frozen stuff when you want to sow. But better yet, see Starting Seedlings and Preparing for spring, sowing seeds, for more about how we grow lettuces in the stored compost over the winter in our greenhouse, then use that compost in spring for seedlings.

Greenhouse beds filled with screened compost.
Photo Wren Vile

Lettuce growing in screened home-made compost in our greenhouse in November.
Photo Wren Vile

We transplant lettuce at 10″ spacing into the beds in mid-September or early October. By harvesting only the outer leaves, we keep those lettuces alive and growing all winter to give us salad from November to February. Because we water the lettuces, the compost organisms stay alive and active. If you don’t grow a crop overwinter, water the compost from time to time to keep it slightly damp.

This system provides us with a large quantity of mellow screened compost for seed flats, indoors and not frozen. The micro-organisms have had plenty of time to colonize the compost, so it is full of life. In spring, as we need space in the greenhouse, we pull the lettuce. We can then scoop out the compost to fill the flats for seedlings.

Aphids

The only issue we sometimes have is aphids in early spring. This winter we are experimenting with some plants we hope will flower in early spring and attract beneficial insects who also eat aphids. I’ll report on this project when we see the results.

Here’s what we currently do to deal with early spring greenhouse aphids:

jet the plants with water to project the aphids into outer space (OK I’m exaggerating),
gather up lady bugs, or
if numbers of aphids are really high, we use a soap spray.

We start our first seedlings in mid-January, although we only sow a few things the first week (cabbage and lettuce for outdoors and tomatoes for our hoophouse), and harvesting just one or two lettuces would provide enough compost for those few flats.

Lettuce transplants in soil blocks. Photo Pam Dawling

Soil blocks

We used to make soil blocks for our more delicate transplants (melons, early cucumbers and squash) because there is no transplant shock when you plant them out. We even used them for lettuces at one time. We developed a very simple recipe, which we seem to have lost, but it was something like 1.5 parts by volume of our home-made compost, 1 part of soaked coconut coir and as much water as needed to make a wet slumpy, but not soupy, mix.

I use coir rather than peat moss, because I believe the extraction rate of peat moss is not sustainable, and as a carbon sink, it’s better to leave it in the ground. Coir is a tropical food by-product. I’m sure it’s better returned to the soil where the coconuts are grown.

The mix is compressed into a special block-maker, which is then scraped across an edge of the container of mix, to create a flat base, and then the block is ejected using the spring-loaded handle into a tray or open flat. We line our flats with a sheet of plastic to reduce drying out. It’s important to dunk the block maker in water between fillings to wash off the old remnants and enable the new blocks to slip out smoothly.

The blocks are surprisingly stable – they can be picked up and moved, like brownies. Or you can move several at once on a kitchen spatula. As the plants grow, the roots get air-pruned. Even if you pack the blocks shoulder to shoulder in the tray, the roots from one block do not grow into the others. There is no root damage at all when the complete block is transplanted. Do make sure you press the surrounding soil down and inwards to make good contact with the block.

Okra seedlings in a Winstrip tray in the greenhouse. Note the vented cell sides.
Photo Kathryn Simmons

Winstrip trays

More recently we have come to love Winstrip trays, very durable plug flats with cubic cells that are vented down the sides, so the plants get air-pruned. The bottoms of the cells have finger-sized holes so you can easily pop a full-grown transplant out of the tray. The Winstrip 50 cell tray has cells almost the size of soil blocks. These flats have all the advantages of soil blocks except price. They are expensive. We got ours used. Winstrips have two additional advantages: they are much quicker to use than soil blocks, and they work with all-compost. We don’t add any coir. One less input to buy. I haven’t calculated how many plugs-worth of coir pay for one Winstrip tray. . .

See this post on using Winstrip trays and transplanting plugs from them

For more about soil blocks, and Winstrip and other plug flats, see my book Sustainable Market Farming

Book Review: High-Yield Vegetable Gardening: Grow More of What You Want in the Space You Have by Colin McCrate and Brad Halm, Storey Publishing, December 2015

This book is intended for home gardeners who value efficiency and productivity. The authors, founders of the Seattle Urban Farm Company, explain techniques used by biointensive farmers and how to adapt these techniques for any size of garden. This professional help will assist gardeners to extend the season, increase yields, maintain healthy soils and deal with pests and other problems. This is not a beginner book telling you how to grow carrots (or any other crop). It will give you the information to choose the variety of carrot best suited to your goals, figure out how much land to put into carrots for the harvest you want, when to plant them, how to get maximum yields and how to have a continuous supply. It is not a book on marketing either. I want to set that out clearly, so no-one buys the book wanting something that it’s not. It’s a very good book if you want to “up your game” and get full potential from the land you have and the time you have available to spend working it.

This 7″ x 9″ spiral bound lay-flat book has 320 pages, including the index and resources section. The cover price is $18.95. It is illustrated with black and white drawings rather than photos, and has green spot color for headings and special sections. This gives an old-fashioned air to the book, until you come upon a drawing of a smart phone. There is nothing old-fashioned about the planning charts and spreadsheets.

After a poor start, on page 222 the gender ratio of the gardeners pictured starts to even up, and ends up close to the national average of 30% of farmers being female.

The book opens with three examples of high-yield gardens: A typical city lot of 5000 sq ft (including the space occupied by the house); a quarter-acre in the suburbs; and a rural one-acre plot. The authors discuss how to make a garden map and determine which factors influence how you use the site (shade for instance), and what your priorities are. They advocate for standard size raised beds in order to simplify planning and to reuse materials like row cover, netting or drip tape.

There are tables of crop spacing and scheduling for 60 annual vegetables and herbs, about 20 perennial vegetables and fruits and 20 perennial herbs. There is a worksheet to help you calculate how much of each crop to aim for, based on the average serving size, depending on your tastes, whether that’s non-stop arugula, tomatoes for canning or a large amount of carrots for a farmer wedding. Some of the charts can be downloaded from the Seattle Urban Farm Company’s website. There is a table of yields and one of planting dates, working from your own frost dates. There is a Planting Calendar Worksheet blank you can copy and use for each crop you plan to grow.

There are clear instructions on designing a crop rotation, including a chart of crop height, life span and fertility needs. They discuss practical limitations that might lead you towards either two rotations within your garden, or a separate rotation for the greenhouse. They urge you to keep good clear records. (Oh so important! Who has time to make the same mistake twice in farming?).

There is a Seed Order Worksheet, and a clear description of the word “hybrid” which has sometimes become a bad word among some gardeners who misunderstand the plant breeding work of the past century or so, and how it has brought us high-yielding, disease-resistant varieties, which are a boon to gardeners wanting high yields. Sure, you can’t save your own seed from hybrids and have it grow true, but who realistically grows all their own seed? So many crops cross with each other; sometimes seed-saving conflicts with getting food from that planting; seed-growing and selecting is a skilled job. Seed companies can do that work for us. I do grow a few seed crops, so I know what is involved. But I also grow many hybrids, and am grateful for them.

In a couple of places the drawing isn’t as good as a photo would be. The Jericho and Winter Density lettuces don’t look so different, and you couldn’t tell the size difference. The high tunnel (hoophouse) inflation blower tubing drawing on p 263 looks very strange to me, like maybe the artist has never seen a real one, and worked from a description.

There is a chart of seed longevity, a subject not always covered in gardening books. There is an excellent chapter on soil tests and interpreting them, which is very down-to-earth. (“We determined this to be about 75 and 50 pounds per 1000 sq ft.”) Nice and user-friendly, it won’t blind you with science. There is another good chapter on irrigation systems, a subject often ignored in backyard gardening books. “Because we strongly believe that hand watering a large, diversified garden site is an inefficient use of time and resources, we won’t even include it as a viable option for garden irrigation.” “Spending valuable hours trailing a hose through the garden is, at best, a poor use of your time.” Absolutely!

Setting up spaces to start seedlings and keeping them well-lit and watered is clearly explained. So is the subject of small greenhouses. The drawing includes the 1970’s craze of lining the back wall with black barrels of water, although the authors do point out that such devices can help, but will not be enough to warm the air to seed germination temperatures. In my opinion, the space given over to big barrels of water would be better given to more plants and the need for heat addressed in other ways!

There is a chapter on starting seedlings and planning for that on a large scale. It includes tips not found everywhere, such as when to sow rootstock and scion varieties for grafting tomatoes, starting cuttings, growing microgreens and hand pollinating. Planting depth is covered, including laying tall tomato plants in a small trench and planting brassicas up to the lowest leaves, rather than the same height as in the seed flat. There are recipes for mixing your own organic fertilizers, and which plants will respond most to extra nutrients. There are tables of organic management strategies for pests and diseases.

Compost-making is discussed, along with a table of Carbon:Nitrogen ratios of various compost ingredients. There is a table of cold-hardy salad crops and information about building low tunnels, caterpillar tunnels and basic types of small hoophouses for cold-weather growing. If you are planning a big hoophouse, I’d recommend getting more information than in this book. There is a chapter on harvesting, washing and storage.

As you’ve probably gathered by now, this is a book full of valuable gardening charts. If you are a grower who doesn’t want to work with spreadsheets, you can easily print off the Seattle Urban Farm Company’s worksheets and use those. Or take the spreadsheets and run. Either way, this is a valuable book for serious backyard growers.

Tag: starting seedlings