Year-Round Growing on the Farm and Garden, starting now

At the Organic Growers School Conference, Ira Wallace and I co-presented a half-day workshop (twice!). I uploaded the slides as a pdf on SlideShare.net, and here they are.

Those who start early in “spring” (late winter) might get earlier crops, but when is it worth it?

Some crops are just not going to thrive if you start too soon: cucumbers, peppers, and even tomatoes, for example. Make sure you can provide conditions that meet the minimum temperature requirements for these tender crops. See my book Sustainable Market Farming, for all the details. We used to start these tender crops earlier than we do now. March conditions have become more unreliable, often colder.

If you already have a place to grow protected crops, or you are experienced with rowcover and have plenty on hand, then the signs are good. Crops can be started earlier in a greenhouse or hoophouse (or even on a kitchen windowsill) than you can sow them outdoors. When the plants reach a good size, harden them off and then plant them out in a mild spell, with rowcover for the first couple of weeks. Pay close attention to weather forecasts.

Our greenhouse full of seed flats and sunshine in March.
Photo Twin Oaks Community

“Hardening off” is a process of acclimating your plants to colder, brighter, breezier conditions, so that they won’t suffer when they are transplanted. If you have only a small number of plants, or of flats, you could actually bring them back indoors every night and set them out every morning for 10-14 days. Growers with lots of crops to harden off will make use of a coldframe. Depending on the actual temperature (or the expected night-time low) we might leave our plants uncovered, use rowcover, top the rowcover with transparent lids (“lights”) , and if it’s going to be really cold, quilted covers, weighted down with wood beams if it is the least bit windy.

Our coldframes and greenhouse at Twin Oaks. Photo Twin oaks Community.

After two weeks of hardening off, look for a few days of mild, calm weather to plant them out in the garden. Water the plants well the day before transplanting, and again one hour before transplanting. This allows the cells of the plants to fill up with water, enough to tide them over the period of “transplant shock”.

Even the most skillful of us end up doing some damage to the roots of transplants, and that means the plants have to regrow some lateral roots and root hairs before they can pull in water at the rate they were doing before your ministrations. As you transplant, avoid touching the roots of the plants. Our fingers damage the root hairs.

Okra seedlings in a Winstrip tray in the greenhouse.
Photo Kathryn Simmons

A way to minimize the root damage is to use soil blocks or Winstrip plug flats. These methods are more expensive in time or money than open flats or bare root transplants, but they allow the roots to get “air-pruned” as they grow. When the roots reach the air at the edges of the blocks, or at the vertical slits on the sides of the Winstrip cells, they stop growing, rather than circle around the cell, causing the plant to get root bound. Secondly, these tools work by helping the roots and compost form a coherent block, one that holds together as you pop it into the hole you create in the soil.

Speedling flats are styrofoam flats with tapered cells, and it is possible to slide the plugs out (or gently pull them out) with little damage. Regular cell packs (4-packs, 6-packs etc) can be encouraged to release their transplants by squeezing them at the base of a cell, while holding the pack sideways. Then spread your fingers over the compost around the pant, invert the pack and hopefully the plant and its compost stays as an item, with your fingers either side of the stem.

Transplanting spinach from a Speedling flat. Butter knives are the tool of choice for easing the little wedges out of the tapered cells.
Photo Denny Ray McElya

Hold the plant with one hand by a seed leaf, or if you have to, by the stem. The seed leaves are disposable, stems and roots are not! Hold the plant at the right height, usually with all the stem below the leaves in the ground and all the leaves above ground. Once the plant is in the ground at the right height, hold it there and use the other hand (maybe with a trowel) to push in soil to fill the hole. Firm the soil down quite well, pulling in more soil as needed to leave a level surface. You don’t want the plant to be in a divot, where water can accumulate.

About the degree of firmness: you are aiming to make good contact between the soil and the plant roots, so the roots are not in air pockets, but rather can suck in water from the between soil particles. Don’t firm so hard that you expel the air from the soil and make what feels like concrete the next day. With cabbages, I was taught to firm enough so that if you then grasp a leaf and pull, the leaf tears off, rather than pulling up the whole plant.

Plant for 20-30 minutes, then pause and water in each of the new transplants by hand. Some people will bring a watering can along the row and water each one, one at a time. I prefer to do little batches. At the end of you transplanting session, water the whole row or bed again. try to avoid having piles or dishpans of plants with roots exposed to the air. Definitely don’t take a tea break if you have exposed plants.

Cover with rowcover if needed, or shadecloth if the weather is very bright and sunny. This will just be for a few weeks, helping the plants recover from the transplant shock, and biding time while spring warms up.

If it doesn’t rain, water again the next day (day 2), then on days 4 and 6, then twice a week, then once a week forever after that, until harvest is completed.

A bed of young transplanted lettuce.
Photo Wren Vile

Preparing for Spring Transplants

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:

  1. jet the plants with water to project the aphids into outer space (OK I’m exaggerating),
  2. gather up lady bugs, or
  3. 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

Twin Oaks Garden Task List for April

Asparagus in early April.Credit Wren Vi
Asparagus in early April.
Credit Wren Vile

All Month:

Lettuce Factory: In flats, (on greenhouse bench) sow lettuce #7, 8, 9 (romaines & small varieties to interplant with peanuts). Transplant 1/3 bed lettuce (120 plants)/week. Plant #4, 5, 6 this month.
Compost Needed for April: 6-9 tractor buckets for beds, 24-30 bkts to disk in.

Early April:

In greenhouse, sow lettuce #7;

Keep celery above 55°F, and celeriac above 45°F (don’t put in coldframe). 10 consecutive days <55°F for celery, <45°F for celeriac, causes bolting.

Spot lettuce, harden off in coldframe. Spot peppers, tomatoes, & eggplant. Protect new pepper seedlings from mice.  Keep tomatoes above 45°F at night, eggplant above 55°F.

Cut sweet potato slips at 6-12”, put in water.  Once a week, plant rooted slips in 4” flats.

Sow outdoors: carrots #5, beets (see March notes), parsnips with radishes #2, (in celery bed), sunflowers.

Weed and thin early crops. Side dress or foliar spray over-wintered spinach to boost production.

Take rowcover from turnips, senposai, cabbage #1, kohlrabi, little alliums, onions as needed for broccoli.

Transplant lettuce #4, main cabbage & broccoli under rowcover (12 pieces) within 6 weeks of sowing.

Till beds for mid-April. Compost beds for late April plantings.

Garlic bulbing is initiated on/after April 10 (13 hours daylight), and soil temperature above 60°F.

Mid April:

In greenhouse sow melons #1 in soil blocks or plug flats, replacement paste tomatoes, lettuce #8, and okra.

Sow beans #1 when lilac in full bloom, sunflowers. Sow edamame #1, corn#1, if warm, and soil >60F.

Till beds for late April (chard, cowpeas, peanuts). Compost beds for early May (okra, toms, melons, celeriac, lettuce 7,8,9, asparagus beans)

Hill up potatoes when 6” high. Cover half the vine. Repeat after 2 weeks. (Flameweed if too wet to hill.)

Take rowcover from kale, collards, early lettuce for raised bed tender crops.

Transplant broccoli #2, insectary flowers #1, bulb fennel, lettuce #5, cukes #1 w/nasturtiums, zukes #1; use spring hoops for cucurbits. Take rowcover from spinach to strawberries.

A fine bed of fava beans. Credit Kathryn Simmons
A fine bed of fava beans.
Credit Kathryn Simmons

Install stakes every 8-10’ for peas and fava beans, and stringweave them to final height of that variety.

Weed garlic [or flameweed it early in the morning after a good rain. Direct flame at base of garlic plants]

Harvest lettuce as heads rather than leaves, from 15 April

#3 Spring Tractor Work (mid April) – Disk areas for sweet potatoes, winter squash, watermelons, (Romas and peppers if no-till cover crop insufficient). Bush-hog late food crop plots when rye heads up, to help clover or peas develop. Also clover patches, eg Green Fallow (All Year Cover Crops).

Late April:

in greenhouse sow lettuce #9; watermelons #1 & 2 in soil blocks or plug flats; calendula and various insectary flowers, filler corn & Romas.

Sow corn #1 (1/2-3/4” deep) in two phases, and peanuts if soil temperature is 65°F. Also cowpeas #1, and sesame.

Sow more leeks if needed in Little Alliums bed outdoors. If not, sow more mini-onions and scallions #3.

Transplant lettuce #6, leaf beet, chard, insectaries; finish transplanting gaps in the main broccoli & cabbage plot, plant Alyssum. Take rowcovers from broccoli & cabbage for new crops.

If mild, plant tomatoes. Harden off nightshades by restricting water.

Till beds for early May (okra, toms, melons, celeriac, lettuce 7/8/9, asparagus beans). Compost beds for mid-May (edamame, eggplant, limas).

Store spring and fall seeds (spinach, peas, beets) in the basement for the summer.

Foliar feed the potatoes, ideally the morning before hilling up, and every 2 weeks.

Roll out Driptape and Biotelos corn plastic mulch for peppers and Romas where no-till cover crop not used.

Cover crops: sow rye to wimp out. Sow buckwheat in any beds not needed for at least 5 weeks eg. leeks limas; add soy if bed not needed for 7 weeks. 

Haybine or bush-hog vetch & rye for no-till planting of Roma paste tomatoes, late in the month (or very early in May). (Mow strips; or till strips through the cover crop for the rows, with narrow-set tiller). Water the area before digging holes, if dry.

Perennials: Weed blueberries, asparagus, raspberries, strawberries, grapes as needed. Mow aisles. If asparagus weeds are getting out of hand, mow down one or more rows to keep control. Monitor asparagus beetles, spray spinosad when bees not flying, if >10 adults/100 crowns. Spinosad: Shake well, 1-4 Tbsp/gall (1fl.oz=2Tbsp=30ml.) Repeat in 6 days.

The black center of this strawberry flower show that it was hit by frost and no berry will develop.Credit Kathryn Simmons
The black center of this strawberry flower show that it was hit by frost and no berry will develop.
Credit Kathryn Simmons

Cover strawberries if frost threatens – take rowcovers from spinach. (Pick flowers off any new spring  plantings.)

Visit grapes, log progress, remove flower buds from new vines. Note deaths and where replacement arms are needed.  Check and repair fruit drip irrigation, thin raspberries to 6/foot of row.

Harvest and weed: Asparagus, chard (hoophouse), collards, garlic scallions- pull at 8″, kale, leeks, lettuce, radishes, rhubarb, senposai, snap peas in hoophouse, spinach.

Starting Seedlings

Seed flats in the greenhouse
Seed flats in the greenhouse

We’ve been starting seedlings since late January, and the greenhouse is filling up with flats of lettuce, cabbage, kohlrabi, spinach, scallions and broccoli. We’re eating our way through the lettuces that grew overwinter in the compost in the block-work greenhouse beds, and shoveling out the compost to fill our flats. All our seedlings are grown in 100% home-made compost. We screen compost to fill the beds in September and transplant lettuce there in October. When we need the compost for the seedlings, it has mellowed nicely and has plenty of worms. This beats buying in bags of compost, or chipping lumps off a heap of frozen compost outdoors in January! Our greenhouse has a masonry north wall and a patio-door south wall. It has no heating apart from the sun (this is Zone 7). This space is warm enough and just big enough for all our seedlings once they have emerged. For growing-on the very early tomatoes and peppers, destined for our hoophouse, we use an electric heat mat and a plastic low tunnel in one corner of the greenhouse. Many seeds benefit from some heat during germination and are then moved into slightly less warm conditions to continue growing. This means it’s possible to heat a relatively small space just to germinate the seeds in. We use two broken refrigerators as insulated cabinets, with extra shelves added. A single incandescent lightbulb in each supplies both the light and the heat (we change the wattage depending on what temperature we’re aiming for). Some people construct an insulated cabinet from scratch, with fluorescent lights suspended above the flats.

Our coldframes and greenhouse
Our coldframes and greenhouse

We use traditional coldframes for “hardening-off” our plants (helping them adjust to cooler, brighter, breezier conditions). They are rectangles of dry-stacked cinder blocks, with lids of woodframed fiberglass. Having heavy flats of plants at ground level is less than ideal for anyone over thirty-five! Shade houses and single-layer poly hoop structures with ventable sidewalls and benches for the flats are a nicer option. Some growers report that some pests are less trouble when flats are up on benches. Others say flats on the ground produce better quality plants. According to the nighttime temperatures, we cover the coldframes with rowcover for 32°F–38°F (0°–3°C), add the lids for 15°F–32°F (–9°C–0°C) and roll quilts on top if it might go below 15°F (–9°C). For brassicas, lettuce and our paste tomatoes (a big planting), we use open flats — simple wooden boxes. The transplant flat size is 12″ × 24″ × 4″ deep (30 × 60 × 10 cm). It holds 40 plants, “spotted” or pricked out in a hexagonal pattern, using a dibble board. For sowing, we use shallower 3″ (7.5 cm) flats. Usually we sow four rows lengthwise in each seedling flat. We reckon we can get about six transplant flats from each seedling flat. This allows for throwing out any wimpy seedlings, and lets us start a higher number of plants in a smaller space. Because we transplant by hand, and because we hate to throw plastic away (or spend money when we don’t need to), we use a range of plastic plant containers. For crops where we are growing only a small number of plants of each variety, we use six- or nine-packs, or a plug flat divided into smaller units.

One year we tried soil blocks for early lettuce transplants, shown here on our custom-made cart
One year we tried soil blocks for early lettuce transplants, shown here on our custom-made cart

The first crops sown are not necessarily the first ones planted out. Our spinach gets sown Jan 24 and transplanted out 4 weeks later. The early tomatoes get planted in the hoophouse at 6 weeks of age (slower-growing peppers go in at 7.5 weeks with rowcover at the ready!). Lettuce goes outdoors after 6.5 weeks, cabbage after 7.5 weeks, cipollini mini-onions after 8 weeks. These are early season timings and as the days warm up and get longer, seedlings grow more quickly. Being a few days later sowing something in early spring makes little difference, as later sowings can catch up by growing faster in the warmer weather. If the spring is cold and late, you may find your greenhouse packed to the gills with flats you don’t want to take outside. We try to put the faster-maturing crops near the doors and keep the open flats, which will need spotting-out, near the accessible north side. But let’s not complain about the bounty of so many plants! Spring is an exciting time of year, full of new growth and new potential. Working in the greenhouse with tiny plants on a sunny day when it’s cold outside is a special treat.