Bare Root Transplants

Lettuce seed bed, with Muir, Jericho, Sierra lettuces. Photo Bridget Aleshire
Lettuce seed bed, with Muir, Jericho, Sierra lettuces.
Photo Bridget Aleshire

Last week when writing about Lettuce Varieties for January I mentioned how we grow all our outdoor lettuce as bare root transplants. From January through to the end of April, we sow lettuce seed in open flats. After that date, we sow in outdoor nursery seed beds, and simply dig up the transplants when big enough and replant them in our raised beds. We transplant 120 lettuce outdoors each week until early October and then transplant in our greenhouse and our hoophouse. We also grow many other crops (all the easy to transplant ones) in open flats, or in nursery seed beds.

This method has gone “out of fashion”, but perhaps it will come back in! Atina Diffley (Author of Turn Here Sweet Corn and Wholesale Success) has written a blog post about bare-root brassica transplants at atinadiffley.com/blog/. She has written a thorough-and-concise 9 page manual Seed Beds: Bare Root Field-grown Brassica Transplant Production.  It includes a chart of pros and cons of bare-root transplants compared to container-grown greenhouse transplants.

Using bare-root transplants does require a bit more attention to technique than popping plugs into the ground. But it’s not that difficult and we train new people every year with success.

Why bare-root transplants?

Bare-root transplants save a lot of time and money, compared to growing in flats. They also save on valuable greenhouse space. The plants get very sturdy, because they have the full depth of soil in which to develop big roots. Starts grown in outdoor seedbeds are already acclimated to cooler conditions than plants in your greenhouse. They are less prone to drying out than seedlings in flats, but do be ready to protect them from bugs.

Which crops work best?

Bare-root transplants can suffer more transplant shock than plugs, so start with “easy to transplant” crops, such as brassicas (cabbage, kale, collards, broccoli, Brussels sprouts, kohlrabi), lettuce, onions and leeks. Tomatoes and peppers are worth trying next. See the Chart “Relative Ease of Transplanting Bare-Root Vegetable Seedlings” free online in Knott’s Handbook for Vegetable Growers. Avoid trying bare-root cucurbits (squash, melons, cucumbers).

Bare-root transplants can be used on any scale, from backyard to large farm. See the impressive photos of huge beds of cabbage transplants in Atina Diffley’s manual. They can be used at various times of year, and from indoors to outdoors and vice-versa.

Spring bare-root transplants started in a hoophouse, planted outdoors.

For the earliest spring transplants, bare-root hoophouse starts are a nice option. For us, onion seedlings overwintered in the hoophouse have worked very well. Seedlings outdoors or in a cold-frame suffer too much winter-kill. We don’t want to fuss with flats in November-February. We’re in zone 7, at 38̊ N. We sow onions in the soil in the hoophouse November 10 and 20, with a backup sowing on December 5. We plant them outdoors as early in March as we can. The onions get to thin-pencil-size by March 1, which we couldn’t do from a spring sowing. Onion roots are tough and thick, not thread-like – they are easy as bare-root transplants.

We sow spinach, collards and kale in the hoophouse in mid-late January and plant them outdoors in early March. This is a lot less work than using flats, and our comparison trials with bare-root spinach showed results were just as good as spinach in Speedling plug flats. We have tried early lettuce transplanted from the hoophouse, but the plants were not as sturdy as those in flats.

Senposai, the Thousand Wonder Green, Credit Kathryn Simmons
Senposai, the Thousand Wonder Green,
Credit Kathryn Simmons

Outdoor bare-root transplants

See my book Sustainable Market Farming, for more details of growing outdoor bare root transplants. We grow lettuce this way from April to September, and fall brassicas in June and July, in one of our permanent raised beds where the soil is friable and free-draining. Also see Atina Diffley’s manual for cultivation tips.

We grow outdoor cabbage, broccoli, collard, senposai and Yukina Savoy transplants in seedbeds for 3-4 weeks in June and July, covered with ProtekNet on hoops. We transplant in July and early August for harvest in October and November. We prefer this to direct sowing, because it is much easier to keep the relatively small seedbed watered and bug-free. For large amounts use an EarthWay seeder. Atina Diffley recommends the leek seed plate for brassicas.

Outdoors to indoors

In September we make an outdoor seedbed for crops to transplant into our hoophouse in October. The late summer hoophouse crops get a few extra weeks to finish up. Because the hoophouse can be warmer than ideal for lettuce germination until well into fall, it often works better to start plants in a cooler location, then move the plants. In September in our climate, four-week old lettuce plants will be a good size.

As well as ten varieties of lettuce, we sow various Asian greens and Brite Lites chard. Nine days later we sow another ten varieties of lettuce, white and red Russian kales, senposai and frilly mustards such as Ruby Streaks, Red Rain, Golden Frills, Scarlet Frills as well as green mizuna. We cover the seedbeds with hoops and ProtekNet and water daily. Transplanting these plants starts October 1 with the fast-growing pak choy, Chinese cabbage and Tokyo Bekana. The other transplants follow, as they reach the right size.

Brassica seedbed protected from insects with ProtekNet and hoops. Photo Bridget Alsehsire
Brassica seedbed protected from insects with ProtekNet and hoops.
Photo Bridget Alsehsire

Stay indoors in winter

In October in the hoophouse we sow short rows of “brassica fillers”, mostly senposai, Tokyo Bekana and Maruba Santoh. These grow fastest, which becomes more important in the dark winter days. We fill gaps in any brassica bed, that occur either because of disease, or of harvesting. In late October and early November we sow filler leaf lettuce varieties and filler spinach. These extra plants help us out if something goes wrong, and give us the chance to grow some extra crops after the first ones have been harvested.

How much to sow

Our formula for sowing seedbeds in the hoophouse is to divide the final row length of brassica plants by 10 to give the minimum length of seed row to sow. These plants will be transplanted 10″-12″ (25-30 cm) apart. For onions (to be transplanted 4″ (10 cm) apart), we divide the number of plants wanted by 20 to give the row feet (67/m), but we sow this amount twice, about 10 days apart. Outdoors for the fall brassicas, we sow around a foot (30 cm) of seed row for every 12′-15′ (3.6-4.6 m) of crop row, aiming for 3-4 seeds per inch (0.75 cm apart). These plants will be transplanted 18″ (46 cm) apart. It’s important to weed and thin the seedlings to 1″ (2.5 cm) apart soon after they emerge.

Transplant age and size

There is quite a lot of flexibility about when a start can be transplanted, but there are accepted ideals to be aimed for. The University of Florida Vegetable Horticulture Program Vegetable Transplant Production page  has a wealth of transplant information. Transplants grown over winter or in very early spring in a hoophouse will take longer to reach plantable size than those sown in spring or summer.

Suitable conditions for transplanting

The ideal conditions for outdoor transplanting are mild windless afternoons and evenings just before light steady rain. Transplanting late in the day gives the plant the chance to recover during the cooler night hours when transpiration is slower. Shadecloth or rowcover can reduce the drying effects of wind and sun. Damp soil is important before, during and after transplanting.

Bare-root transplanting technique

When you dig up your bare-root transplants, leave some soil clinging to the roots, to help the plants re-establish quicker. They don’t need a full handful of soil for each plant. Just dig up a clump and give it a light shake, to leave the majority of the soil behind, and some still on the roots. This means less damage to the root hairs. Be sure to dig deep enough so you don’t damage the tap roots. Water your plants the day before and an hour before lifting (pulling) them. In hot weather, keep the plants as shaded as possible while transplanting.If necessary water the soil ahead of planting.

We use plastic dish-pans to carry our plants from seedbed to field, and I tell people to only dig up what they think they can transplant in half an hour, so that plants don’t sit around for too long. Push the trowel into the soil, using the dominant hand, push it forwards, shake a plant loose from the clumps in the dish-pan with the other hand, and slip a plant in behind the trowel. Pull out the trowel, keeping it in your hand while you close the soil against the stem with your planting hand and the trowel. (Efficient workers keep a hand on the trowel at all times, never setting it down.) Move to the next spot and repeat. When setting out a large number of plants, water every 20-30 minutes if you don’t have drip irrigation running (a bit less often if you do) regardless of the number of plants set out. If the person is skilled and moving fast, and the weather is not outrageously hot or windy, I might let an hour go by before pausing to water. The advantage of getting a lot of plants in the ground proficiently and quickly might outweigh the need to water more often, as the plants are not having their roots exposed to the air for as long when they are planted fast. The hand-watering really helps the soil settle around the roots, and after that the damp soil can wick moisture from the irrigation towards the plant.

Aftercare: water, rowcover, shadecloth

Water your plants the day after transplanting, on days 3, 7 and 10, and then weekly, if it doesn’t rain when you’d like it to. Shadecloth draped over recently transplanted crops can help them recover sooner from the shock in hot sunny weather. We use 50% shade, in 6′ (1.8 m) width, with wire hoops to hold the shadecloth above the plants. This improves the airflow as well as reducing the abrasion or pressure damage done to the plants. The airflow through shadecloth is better than with floating rowcovers. ProtekNet allows good airflow too, and keeps bugs off.

Shade cloth on lettuce seed bed. Photo Nina Gentle
Shade cloth on lettuce seed bed.
Photo Nina Gentle

 

 

 

Colorado potato beetles, germinating lettuce, wheelhoes

A ladybug on a potato leaf, looking for pests to eat Photo Kathryn Simmons
Not a Colorado potato beetle: A ladybug on a potato leaf, looking for pests to eat
Photo Kathryn Simmons

Our spring-planted potatoes are just starting to flower, and I’m now in my weekly routine of monitoring for Colorado potato beetles. I walk the length of the patch and back, switching rows every 9 paces or so. I squish and count the adult CPB, and also count the larvae (I don’t always squish all of those). Did you know you can tell a squashed female CPB from a squashed male? The females are full of orange eggs, until you squash them, that is, then the orange eggs are all over your fingers!

Potato plants can tolerate 30-40% defoliation early in life, 10-60% defoliation during middle age, and up to 100% defoliation at the end of the season without reducing the yield.So don’t panic! But do pay attention. The Action Level for Colorado potato beetle is 1 adult per plant, and that for larvae is 2 per plant. Our rows are 265 ft this year, and the plants are 12″ apart, so I’m looking at 530 plants when I go down and back. So far, we’re doing great. Last week I found 12 adults. This week I found 5 adults and 41 larvae. I still don’t need a mass slaughter program. If we need to spray I’ll use Spinosad. For home gardens you can buy Monterey Garden Insect Spray from Seven Springs Farm in Virginia. Or elsewhere. It is OMRI approved but is very toxic to bees (and Eastern Oysters, should you need to know), so we only spray Spinosad at dusk when the bees have gone home, and make sure not to pour the rinse water from the sprayer into the drains (which go via our septic system into the creek). Generally I use the driveway as a large inert area to spread the wash water over.

But I only use Spinosad if we have to. Another part of my plan is timely mowing of the clover patch next to the potatoes. The clover mix was undersown in the fall broccoli last year, and in the spring we simply bush hog that patch every time the weeds are getting too successful compared to the clover. Or ideally, before that happens. We had flowering crimson clover there earlier, and mowed that. Now what we see is white clover. there is red in the mix too, but I haven’t seen that flowering yet. Our hope/plan is that when we mow the clovers, many of the beneficial insects move over to the potato patch and eat the CPB.

At the great link I gave earlier, Andrei Alyokhin provides good information on the life cycle of the CPB, lots of resources, and a lovely collection of Colorado potato beetle haiku (traditional Japanese poetry) written and illustrated by Mrs. O’Malley’s second-grade students from the Old Town Elementary School in 2008 or so, somewhere in Maine I think. The poetry gives new perspectives as we walk the rows searching for the wee beasties.


Germinating lettuce seed

Some weeks I wonder what to blog about. This week I was helped by a neighboring grower who asked me questions about how I germinate lettuce. Aha! A timely topic! We try to grow lettuce for harvest all year round, here in central Virginia, and exactly how we do that varies with the season.
New flats of lettuce seedlings Credit Kathryn Simmons
New flats of lettuce seedlings
Credit Kathryn Simmons

From January until mid-March I sow in flats in the greenhouse, with heating to get the seeds germinated, then good old solar energy to grow them to transplanting size.

From mid-March to the end of April I sow in flats in the greenhouse, without extra heat.
Spring lettuce bed. Photo Wren Vile
Spring lettuce bed.
Photo Wren Vile

From May to late September I use an outdoor nursery seedbed and do bare-root transplants (heat-tolerant varieties). The soil temperature does not vary as much as the air temperature, so I don’t worry about cool nights.

From June I put shade-cloth over the lettuce seedbed, and only sow in the evening.
In July and August I put ice on top of the newly sown rows, under the shade-cloth.
baby lettuce mix in the hoophouse. Photo Twin Oaks COmmunity
Baby lettuce mix in the hoophouse.
Photo Twin Oaks Community

After that I sow lettuce mix in the hoophouse. (Click the link to see my Hoophouse in Fall and Winter slideshow.)

New Seed-Starters Handbook

Knotts handbook
Knotts handbook

There’s a chart of germination at various temperatures in Nancy Bubel’s New Seed Starter’s Handbook and in the Knott’s Handbook for Vegetable Growers which is all online.The soil temperature range for germination of lettuce seeds is 35-85F, with 40-80F being the optimum range and 75F the ideal soil temperature. At 41F (5C) lettuce takes 15 days to germinate; at 50F (10C) it takes 7 days; at 59F (15C) it takes 4 days; at 68F (20C) only about 2.5 days; at 77F (25C) 2.2 days. Then time to germination increases: 2.6 days at 86F (30C); after that it’s too hot.

A soil thermometer soon pays for itself and saves lost crops and frustration. If it’s too hot, find a cooler place (put a seeded flat in a plastic bag in the fridge or on the concrete floor in the basement). Or cool down a small part of the world. That’s what I do when I sow in the evening, water with freshly drawn cold water, line up ice cubes along the seed rows, and cover with shade cloth.

And finally, to a tool we use a lot at this time of year (when the weather is dry enough for hoeing to be successful): our Valley Oak Wheel Hoes. We have two, both with pneumatic tires (rocky soil jars your wrists, think long-term). We have one with the standard 8″ blade and one with a 10″ blade. We use them for the aisles in our raised beds, for between rows of corn, anywhere without mulch. They are very energy efficient, compared to a hand hoe. And some of the crew treat he opportunity to wheel hoe as a chance for an aerobic workout. Others use a more moderate speed.Cover more ground with less effort, and hence, get more done before the weeds get too big to hoe.
The handlebar height is readily adjustable, the blade assemblies can easily be switched from one tool to another (buy one wheelhoe and several different width blades), there are other attachments such as  a small furrower, a one-sided hiller and a 3-tine cultivator. And there are plenty of replacement parts available: we just ordered spare blades after wearing ours down to narrow strips.9_zoom_1413981475